Sit on it

Where do you sit ?

(the following observations based on attending too many lectures)

Ever wonder why a lecture room, auditorium or any place of gathering only seats a small proportion of the total allocated ?

This is because of the different types of people that inhabit such environments. First you have the quick thinking and smart (OK, anyone like me) individual. These turn up on time and head straight for the middle of the row, they wait and observe the other participants arriving.

Next comes the slower ones. They will need to choose a row and enter from one end, carefully deciding how close to sit to the clever buggers who got there first.

Some will rush up and take a seat next to those already sitting. If they are mildly annoying they will say hello and then stare vacantly ahead for the remaining time until the event commences. If they want to be really annoying they will inquire about the weather, why others are present and may even expose their uninformed views on the subject matter for the evening. They may chatter until the commencement of proceedings. Such people are rarely invited back.

Now here come some more, but this time they may not like those already seated. They will choose a seat some distance from those seated, perhaps four to five away. And for extra protection a bag (or whatever they have) will be placed between them and the idiot further along the row. But they have to be careful not to sit too far to the end, as they may encounter the worst individuals of all.

The most common spacing will be with one seat between people. This is throwback to childhood when schoolchildren were instructed to stand at least one arms length apart. A measurement of the distances between people will confirm that some practices persist into adulthood.

Now the worst of all, the person who sits at the end of the row. This obnoxious individual is obviously unaware of problems they cause to others. Everyone else has to squeeze pass them to get to a seat somewhere in the middle. If you are trying to pass, be sure to carry a bag or case and gently smack them in the face as you pass.

Now everyone has arrived and seating is complete. But here comes the speaker/lecturer. Some of these may attempt to break the seating formation. “OK, everyone. Don’t sit at the back. Come on down, there are plenty of seats at the front. Come on now, I won’t bite. I just want us to all get cosy today”. Under no circumstances should you move. People have already spent good time and effort in acquiring their seats. They are not going to move. So just cross your arms, lean back in your chair and give them a look of “Buggered if I’m going to move”. Eventually any efforts to get you to move will be unsuccessful. You can stay where you are.

So now we have it, a few in the middle, the idiots on the end some more scattered in the remaining seats. This formation can be seen in as a graphical representation of the bell shaped curve of intelligence. The intelligent ones in the middle, with those of lesser intelligence on the extremity of each row. And everyone wondering “Why did I come here ?”.

So, Where Do You Sit ?

NB 28/11/2003


Written by William Shakespeare
Directed by Ross Gumbley
Featuring Mark Hadlow and Lara Macgregor

Shakespeare’s darkest and most powerful tragedy tells the story of Macbeth, the brave general who, returning victorious from battle, witnesses a prophecy from three witches that he will one day become King.

Driven by his ambitious wife, Lady Macbeth, the idea of being king grows into an all-consuming desire for power. After murdering the King, Macbeth takes the throne, dispatching all that get in his way. But the witches have another prophecy, one that will end Macbeth’s treacherous rise to power, one that will play out to its bitter and bloody end.

A sharp warning of the infectious and corrosive lure of power, Shakespeare’s Macbeth still reigns supreme after 400 years. To see it onstage is to see our own society played out before us, set in a world we can all relate to.

This suffers from the same thing all the Shakespeare I have seen. Due to the actors slavishly adhering to the old style prose and delivery, it’s often difficult to determine what’s going on. In fact halfway through the first act it all rumbled over me and became boring. By the time I got used to the language in the second half, it was drawing to a rather predictable close. It’s the ‘John Carter’ film problem. All the themes seem old and derivative because they are seen so often. But this is actually the origin of a lot of the plots we see in modern storytelling. (2/5)




Gravity Waves

UC Connect: Black holes making waves around the Universe

Professor David Wiltshire, Department of Physics and Astronomy
Monday, March 7, 2016 from 7:30 PM – 8:45 PM
C1 Lecture Theatre, University of Canterbury

On 14 September 2015 the two LIGO detectors measured gravitational waves for the first time ever, produced by the collision of two black holes 1.3 billion light years away. This opens a new era of astronomy, a window on things we cannot observe by other means. It vindicates Einstein’s 100 year old prediction of gravitational waves, and the rotating black hole solution of Einstein’s equations discovered in 1963 by New Zealander Roy Kerr.

In measuring distance changes a thousandth the size of a proton, this is also the most sensitive measurement ever achieved by humankind. It represents the culmination of four decades of work by thousands of experimental physicists, engineers, mathematicians, numerical modellers and astronomers, who together have had to overcome challenges in fields as diverse as seismology and fundamental quantum optics. Last December, the LISA pathfinder satellite was launched, the first step in taking gravitational wave detection to space. This lecture will reflect on what has been achieved, the technological spin-offs and challenges ahead, and what we might discover in the new age of astronomy ahead.

Notes from wikipedia:
Gravitational waves are presently understood to be described by Albert Einstein’s theory of general relativity. In the simplest cases, and certain less-dynamic situations, the energy implications of gravitational waves can be deduced from other conservation laws such as those governing conservation of energy or conservation of momentum.

On 11 February 2016, the LIGO collaboration announced the detection of gravitational waves, from a signal of two black holes with masses of 29 and 36 solar masses merging together about 1.3 billion light years away.

During the final fraction of a second of the merge, it released more power than 50 times that of all the stars in the observable universe combined. The signal increases in frequency from 35 to 250 Hz as it rises in strength. The mass of the new black hole obtained from merging the two was 62 solar masses. Energy equivalent to three solar masses (our sun is 1 solar mass, 2×10^30 Kg) was emitted as gravitational waves in about 1/10 of a second. The signal was seen by both LIGO detectors, in Livingston and Hanford, with a time difference of 7 milliseconds due to the angle between the two detectors and the source. The signal came from the Southern Celestial Hemisphere, in the rough direction of (but much further away than) the Magellanic Clouds. The confidence level of this being an observation of gravitational waves was 99.99994%.

Amplitude: Usually denoted h, this is the size of the wave — the fraction of stretching or squeezing in the animation.
Gravitational waves passing through the Earth are about 10^−20m.

Wave amplitudes from the Earth–Sun system
We can also think in terms of the amplitude of the wave from a system in circular orbits.
Suppose that an observer is outside the system at a distance 0.08 Light Years (7.5 x 10^14m) from its center of mass. Typical amplitudes will be h ≈ 10^−25m. This is well under the detectability limit of all conceivable detectors.

Power radiated by orbiting bodies
Two stars of dissimilar mass are in circular orbits. Each revolves about their common center of mass (denoted by the small red cross) in a circle with the larger mass having the smaller orbit.
Two stars of similar mass are in circular orbits about their center of mass

Gravitational waves carry energy away from their sources and, in the case of orbiting bodies, this is associated with an inspiral or decrease in orbit.  Imagine for example a simple system of two masses — such as the Earth–Sun system — moving slowly compared to the speed of light in circular orbits. Assume that these two masses orbit each other in a circular orbit in the x–y plane. To a good approximation, the masses follow simple Keplerian orbits. However, such an orbit represents a changing quadrupole moment. That is, the system will give off gravitational waves.

In theory, the loss of energy through gravitational radiation could eventually drop the Earth into the Sun. However, the total energy of the Earth orbiting the Sun (kinetic energy + gravitational potential energy) is about 1.14×10^36 joules of which only 200 joules per second is lost through gravitational radiation, leading to a decay in the orbit by about 1×10^−15 meters per day or roughly the diameter of a proton. At this rate, it would take the Earth approximately 1×10^13 times more than the current age of the Universe to spiral onto the Sun.

In Fiction: An episode of the Russian science-fiction novel Space Apprentice by Arkady and Boris Strugatsky shows the experiment monitoring the propagation of gravitational waves at the expense of annihilating a chunk of 15 Eunomia the size of Everest. The novel was written in 1961 and published in 1962, exactly at the time when Soviet physicists Michail Gerstenstein and Vladislav Pustovoit prepared and published their proposal on using laser interferometry for gravitational wave detection.


2004 Film Reviews

Film Reviews from Film Appreciation Course Feb/Mar 2004

As a result of these classes I have moved from being un-informed and ignorant to informed and stupid. So here it is…..
For my records and your reading, a quick review of the films viewed and, as is the convention, a rating for each.

Nobody’s Business
Before seeing this film, I always regarded the documentary style as being more suited to TV. However this film prompted me to see “The Fog of War”. This film only succeeds due to Alan Berliner’s mix of cinematic styles, all gel to form a compelling narrative of his cranky father. An enjoyable movie with a old man in a starring role you are not likely to forget quickly.

Rating 7/10

The Man with a Movie Camera
This was a surprise for me. I didn’t believe that any film from 1929 could be so inventive and “modern”. Even now it has relevance in a western post-industrial society. It just shows how little most of our lives have changed. It’s just a great kaleidoscope of shapes and movement.

But most of all, I liked the music. The film shown had a soundtrack by “The Alloy Orchestra”, I have since found another by “The Cinematic Orchestra” which I own. And recently found another by the group “Biosphere”, it’s the second disk on their “Substrata V.2” album. This one is described as ambient and all I can find is a reference at to the CD.

Rating 9/10

I had never heard of this film before seeing it. It’s mix of day-glow colours and computer animations form a wonderful stylistic whole.

One scene that remains in my memory is when Amelie is skimming stones. The camera starts behind her, arcs over and after almost 180 degrees ends in front of her. The camera movement is similar to Peter Jackson’s films, both often have the viewpoint up high, with the camera sweeping down to the subject in detail.

Best of all is it’s witty and often dark humour. I didn’t think I would enjoy a film where I had to _read_ all the dialogue. This one goes on my list of “Best Films Ever”. Perfectly formed.

Rating 10/10

Heavenly Creatures
I had seen this film when it was first released and later when it was screened on TV. This is the film where you can see Peter Jackson for the first time as a world class director. He manages to keep the pace of the film going at the right speed, varying where necessary and reaching a slow build-up of tension towards the end. This despite knowing what the end will be from the very beginning.

His mastery of the medium displayed in this film I’m sure is what gave New Line the confidence to spend 200-300 million and 8 years on the biggest film trilogy of all time.

It would be a mistake to make direct comparisons to the other Jackson films. I have read a biography of Peter Jackson and it is clear that his partner Fran Walsh was a big influence in Peter making this film and in it’s execution. I think this is better than his later film “The Frighteners”.

Rating 10/10
(Jacksons second best film to LoTR)

400 Blows
Grey, bleak, dull and boring sum up this movie for me. I can’t believe this could be enjoyed by anyone except for the directors friends and family (including his parents).

This film starts off slowly and gradually progresses to something even slower and duller. I was not impressed, I couldn’t even keep awake and missed 10-20 minutes near the end due to falling asleep. Did anything happen ?

Rating 0/10 (recommended for insomniacs)

Dancer in the Dark
I’m sure that one of the first things they teach in film school is…… hold the camera steady to get a good shot. Avoid sudden movements, quick panning and excessive zooming. In the first five minutes of this film, all the above “rules” were broken. There is a photo in the biography of Peter Jackson, it shows him with a custom made rig to hold the camera steady. Peter went to a lot of trouble to get a steady camera, something Lars von Trier hasn’t bothered with in this film. At first I thought it was some sort of cheap introduction, I can understand using a hand-held camera to enhance movement and intensity. Jackson does this at the end of “Heavenly Creatures” and it works. In this film it doesn’t, if this is “experimental” then the experiment failed. If it’s part of the “style” then it completely undermines the telling of the story. And what is worse is that after 20 minutes I was starting to get a headache.

I actually like Bjork’s music (I have most of her albums), but as an actor she is not very engaging. There were no characters I could relate to and story of minimal interest. I liked the musical numbers (here the cameras were nailed down !) as they added a lightness and diversion to an otherwise below average movie.

I hope that next time, the director employs a better camera operator.

Rating 0/10 (for the headache)

I saw Casablanca for the first time on TV several years ago. So I was a bit surprised to find the film in black and white. I presume this is one of the films given a dash of colour at a later date. When I first saw the film, I thought it was about a “femme fatale” who manipulates men to her own advantage. Seeing the film again my opinion is unchanged.

Ingrid Bergman is, as usual, stunningly beautiful and succeeds in her escape mission; have you ever seen a beautiful woman ask a favour of a man and not get one ?
She does manage to string two seemingly intelligent men along for most of the film, putting on the charm when necessary.

I may also be that I just can’t relate to Bogart as the “Hero”. He doesn’t look or act like one, he looks more suited to a Hollywood gangster movie (and as the bad guy). The best character was the French policeman.

There is no doubt that the film succeeds in atmospherics and style.

I do find it amusing that critics think the film makes a lot of references to other cultural references like Huck Finn, Washington etc and see it as propaganda. I think the general public would not see anything beyond the story. Or perhaps it’s just that I am not American.

Still, a good story and enjoyable. Even if it just perpetuates the myth that the Pretty Women always get what they want.

Rating 6/10

Goldiggers of 1935
The musical numbers have a great style and panache, mixing conventional and experimental film making techniques. The remaining story was a bit of a cliche of goof-ball comedies of the period. It did have wit and a dry humour that kept the story going. But ultimately it’s the musical numbers (especially those pianos) that remain as memories of the film.

Rating 6/10

Citizen Kane
I can see why this film is appreciated by those in the film industry. It sets a lot of standards for others to follow. I don’t know what all the fuss is about “Rosebud”, it’s clear to me that the sled represents the memories of Kane as a child, of a simpler and innocent time he is trying to recapture.

A good and intriguing film that keeps you interested until the end (and isn’t that what it’s all about?).

Rating 7/10

Bowling for Columbine
After a considerable amount of publicity, I saw this film in the theatre when it first came out.
Michael Moore is unashamedly the centrepiece of the movie. This is what gives all the interviews and stunts their cohesion and focuses the film. It would be a mistake to see this as Moore’s ego in flight. He has a self-depreciating sense of humour that may be more obvious in his TV show. I think Moore understands the medium as well (if not better) than his critics and deliberately puts himself forwards as Satan’s little helper, prodding and needling people into saying (and doing) things they would not do if he was located behind the camera.

Ultimately is success as a great social commentary on America, even it it reaches no conclusion.

Rating 8/10


So, overall I enjoyed the course; 8 out of 10 (better than usual) evenings I enjoyed. And there were only three films I had seen before.

Nigel Baker 13/4/2004


Why I don’t go skiing

Skiing isn’t a good idea. You need to be rich, flash and stupid. Let me explain.

First you will need to go shopping. Start with lots of money, you will be needing everything you can lay your hands on.

Now find a ski shop. These are only open in the winter. During the summer months they are usually used by some obscure charity organization selling hand crafted walnuts from Bolivia.

First you will need skis. These are 2m long planks. You may think they are for conveying you gently down a slope. This is not true. They are levers, inevitably your body will not be traveling in the same direction as the skis. Because high tech materials comprising wood and plastic are stronger then flesh and bone, injuries to sensitive parts are inevitable.

Expect injuries due to broken legs, sprained ankles and twisted knees to persist into old age. To protect your legs from protruding rocks, and wind blown snow you will need trousers.

These come in two styles :

The first is a skin tight, body hugging (show every curve) type. You should only consider purchasing these if someone (apart from spouse or family member) considers that you have sexy legs.

If you have sexy legs and breasts you should consider the full body suit. This body enhancing multicolored condom will ensure a quick response should you receive an injury.

The second style is the retro eighties styled baggy trousers. These tents will provide you with an accompanying wind song as you plunge over a cliff to your death. They will also provide men with camouflage should they have an involuntary response to the type one body suit.

You will need torso protection. Here the color is important. You will require something with sufficient color so you can hide in a tow queue. But not too bright or the keas will mistake you for a shiny object to either attack or take back to the nest as a plaything for the chicks.

Eye protection is a must. Again there are two choices.

The first is the dark glasses. These are available in a range of prices to match your social status. Expect to pay more for these than you did for your prescription glasses.

The second type is goggles. These can provide full face protection and camouflage. Especially useful when it’s your turn to clean up the mess at the end of the day.

You will also need pointed steel sticks, with a depth gauge in the end. This is used to prod others in the backside if they get in the way. The depth gauge is to ensure you don’t rupture any bowels. To make things even more dangerous, you will require two.

Now that you have spent several thousands, you have completed most of the spending. Soon you will be expected to spend only hundreds of dollars per day.

At about 11pm the night before your big day, expect your drunk friends to phone reminding you to be up early for the 7am start. They will inevitably arrive about 8am, after some of the company have forgotten to pack sufficient alcohol for the day.

If you are going to Mt Hutt be warned. When scaling the mountain the driver will remark at every bend “It’s about here that the strong winds will blow us over the side to the rocks below”.

If you are fat, expect to be asked to sit on the bonnet to provide traction for the final near vertical climb to the car park.

If you have been spending the first hour of your journey bragging about your gym work-out routine, be expected to push the car. If you have been comparing yourself to Hercules, be expected to lift the car while the chains are fitted.

It is a good idea to inquire of your friends if they have experience fitting chains to the correct wheels. If they hesitate only slightly, give them up for those who know what they are doing.

When you finally arrive you will require tow tickets. The queue should be about 50m long, but don’t worry, this is deliberate. You will need the practice at waiting when you get to the tow queue.

Now for the fun part of your day, getting up that white hunk of rock. The gray things on the snow are not fallen, fashion free skiers. They are rocks. You have arrived either early in the season before the snow maker has been repaired, or late when the snow is beginning to melt, and your family is spending their time at the beach. Remember that in New Zealand the ski fields are covered in tussock during summer.

Your method of getting to the top may vary. If your tow ticket was very cheap, expect to grab a hold of the farm tractor before it leaves.

A club ski field may have a rope tow. Don’t try grabbing the rope with your hand, that’s what a nutcracker is for (and don’t attempt to crack any nuts with it). After a day you will begin to develop upper body muscles. By the second day the pain should subside and you can start skiing properly.

The better ski field will have a “T” bar. This giant hook is for you. Just snuggle up closely to that geriatric old fart trying to reclaim his youth and wait.

When the hook hits you three thing can happen –
1. You could be taken safely to the top, but that is unlikely.
2. You could lurch forward, tangling your skis with your partner and falling in a heap in the path of the next pair of skiers.
3. Or you could sit down (a common error of the uninitiated). This will find you on your bum, sitting on your skis, sliding backwards into the tow queue. The sticks of those waiting should stop you. Just hope that they don’t use them in a horizontal manner, with the depth gauges removed.

Once you have mastered the art of rising gently to the top of the hill and tumbling down again you can call yourself a skier. By about 2pm you will get bored with all this and join your friends in the public bar. Don’t worry about your driver not drinking, this is a kiwi custom. Anyway it’s all downhill to home, you will make it home eventually.

When you finally get home (the same day unless you have stopped at a hotel on the way) you can relax.

Now reflect that it would have been better to stay in bed on a winters day and read.

And that’s why I don’t go skiing (anymore).

Nigel Baker


Ergonomics – The Human Factor

By Jim Oren

(This Article was excerpted from the Antic Online’s Professional GEM Column)
Reprinted without permission from STart Magazine Volume 4 No 1 (August 1989)

A reader of a novel or science fiction story must suspend disbelief to participate in the story. If the author’s grammar or plot it clumsy, it jars the reader and breaks down the illusion., pulling the reader out of the story. Similarity, a software designer who fails to pay attention to the speed and consistency of a program’s interface will distract users from the programs functions and detract from the care that has been lavished on the function of the program.

Making an interface fast and useable is often treated as a black art.. It isn’t – there are well known methods derived from the field of ergonomics, the study of interaction between man and machine. The ergonomics of the human computer interface were studied extensively at Xerox PARC, the birthplace of the Alto, Star and smalltalk systems which led to the Macintosh and the Atari ST. The designers of these original systems knew and applied the principles of ergonomics.

What follows is a short venture into the world of ergonomics. You will find more than the usual quota of math, slated with examples of real design problems. But there is no way print can convey the vibrancy and tactile pleasure of a good interface, or the sullen boredom of a bad one.. The best way to make ergonomics real is to look for your own examples . Get out your favorite arcade game and see if you can spot some of these principles in action. Dig out the most annoying program in your reject pile and look for the mistakes. Then look at your own with a critical eye.


We’ll start right at the users fingers with the basic equation governing the positioning of the mouse, Fitt’s Law:

T = I x LOG2(D/S + 0.5)

T is the amount of time to move to a target
D is the distance of the target from the current position.
S is the size of the target, stated in equivalent units.
LOG2 is the base 2 (binary) logarithm function
I is a proportional constant, about 100 milliseconds per bit, which corresponds to the human’s “clock rate” for making incremental movements.

We can squeeze an amazing amount of information out of this formula when attempting to speed up an interface. Since motion time goes up with distance, we should arrange the screen with the usual working area near the center, so the mouse will have to move a smaller distance on average from a selected object to a menu or panel. Likewise, any items which are usually used together should be placed together. The most common operations will have the greater impact on speed, so they should be closest to the working area and perhaps larger than other icons or menu entries. If you want to have all operations take about the same time, then the targets furthest from the working area should be larger, and those closer may be proportionately smaller.

Consider the implications for dialogs. Small check boxes are out. Large buttons which are easy to hit are in. There should be ample space between selectable items to allow for positioning errors. Dangerous options should be widely separated from common selections.


If you used the ST desktop for any period of time you’ve probably noticed that your fingers know where to find the file menu. This phenomenon is sometimes called “muscle memory” and its rate of onset is given by the Power Law of Practice:

T(n) = Y(1) x n-a

T(n) is the time on the nth trial
T(1) is the time in the first trial, and is approximately 0.4.

The first thing to note about the power law is that it only works if a target stays in the same place. This should be a potent argument against rearranging icons , menus , or dialogs without some explicit request by the user. The time to hit a target which moves around arbitrarily will always be T(1).


Just as fingers are the way the user sends data to the computer so the eyes are the channel from the machine. The rate at which information may be passed to the user is determined by the “cycle time” of the user’s visual processor. Experimental results show that this time ranges between 50 and 200 milliseconds.

Events separated by 50 milliseconds or less are always perceived as a single event. Those separated by more than 200 milliseconds are always seen as separate.

Suppose that your application ‘s interface contains an icon which should be inverted when the mouse passes over it. We know that flipping it within 1/20th of a second is necessary and sufficient. Therefore if a “first cut” at the program achieves this performance, there is no need for further optimization, unless you want to interleave with other operations.

If it falls short, it will be necessary to do some assembly coding to achieve a smooth feel.

On the other hand, two actions which you want to appear distinct or convey two different pieces of information must be separated by an absolute minimum of a fifth of a second, even assuming that they occur in an identical location on which the users attention is already focused.

It should be quickly added that stimulus enhancement will only work when it unambiguously draws attention to the target. Three or four blinking objects scattered around the screen are confusing, and worse than no enhancement at all.

Short Term Memory

Both the information gathered by he eyes and movement commands on their way to the hand pass through short term memory (also called working memory). The amount of information that can be held in short term memory at any one time is limited. You can demonstrate this limit on yourself by attempting to type a sheet of random numbers by looking back and forth from the numbers to the screen. If you see like most people, you will be able to remember between five and nine numbers at a time. So universal is this finding that it is sometimes called “the magic number seven, plus or minus two”.

he shirt-term capacity sets a limit on the number of choices which the user can be expected to grasp at once. It suggests that the number of independent choices in a menu should be around seven, and never exceed nine. If this limit is exceeded then the user will have to take several glances, with pauses to think in order to make a choice.


The effective capacity of short term memory can be increased when several related items are mentally grouped as a “chunk”. A well designed interface should promote the use of chunking as a strategy by the user. One easy way is to gather together related options in a single place. This is one reason that like commands are grouped into a single menu which is hidden except for the title . If all the menu options were “in the open” the user would be overwhelmed with dozens of alternatives at once. Instead a “show info” command, for instance becomes two chunks: pick file menu, then pick show.

Sometimes the interface can accomplish the chunking for the user. Consider the difference between a slider bar in a GEM program and a three digit entry field in a text mode application. Obviously, the GEM user has fewer decisions to make in order to set the associated variable.


This article is a modest sampler from a much larger field. The Card, Moran and Newell book was the primary source for this article.

Stuart K Card, Thomas P Moran & Allen Newell :
The Psychology of Human-Computer Interaction
Lawrence Erlbaum Associates, Hillsdale, New Jersey 1983
(fundamental and indispensable. This volume of experimental results make it weighty. The good parts are at the beginning and end)

Macintosh User Interface Guidelines – Inside Macintosh
Apple Computer, Inc. 1984
(Though not everything translates this is a fine piece of principled design work)

James D Foley, Victor L Wallace and Peggy Chan
The Human Factors of Computer Graphics Interaction Techniques
IEEE Computer Graphics (CG&A) Nov 1984 pp 13-48
(A good overview, including higher level topics. Excellent bibliography)

J D Foley and A Van Dam
Fundamentals of interactive computer graphics.
Addison Wesley 1984, Chapters 5 and 6
(If you can’t get the article above, read this. If you are designing graphics applications, buy the whole book. Staggering bibliography)

Ben Shneiderman
Direct Manipulation : A step Beyond Programming Languages
IEEE Computer August 1983 pp57-69
(What do Pac-man and Visicalc have in common ? Shneiderman’s analysis is vital to creating hot interfaces.

Oren, Tim
Professional GEM
Antic Online, Compuserve
(The complete text of this article and several others on the same topic are included in Tim’s Professional GEM column in the index section of Antic Online. Log onto CumpuServe and type GO ANTIC)

Tim Oren was a member of the original GEM Team at Digital Research and designed the GEM resource Construction Set, later ported to the Atari ST. After leaving DRI he designed the GEM version of KnowledgeSet’s Graphic Knowledge Retrieval System, one of the first hypertext systems available for CD-ROM. At the same time he was the author of the Professional GEM series of online columns in Antic Online and contributor to the inaugural issues of Start. Tim is currently employed by Apple computer’s Advanced Technology Group, where he leads a project in multimedia information retrieval. (1989)


Lexx 3.07 & 3.08



Lexx 3.07 – Tunnels

Kai is brought before “The Commission”, who, in a room full of candles, endeavour to civilly interrogate him, exploring his human evil. Kai is not interested, and requests to be thrown off the tower. The adjudicatrix asks him whether he has killed anyone as an assassin. Kai then delivers his famous speech: “I have killed mothers and their babies. I have killed great philosophers and proud young warriors. I have killed the evil and the good, the intelligent, the weak and the beautiful, but it’s been a while since I slaughtered a whole room full of petty bureaucrats”. Meanwhile, Stan encounters an amateur surgeon, who feels that he has parts that “he’d feel better without”. Prince plays good guy, and dies saving Stan. He wanted Stan to love him. Xev plays with some girls who like bear traps.


Lexx 3.08 – The Key

Using an incarnation in Xev’s image, Prince continually probes Kai, 790, and Stan, asking for a way to get the key to the Lexx. They hook Stan up to 790’s diagnostics and Kai determines that the key could be released during sexual rapture, instead of the ecstasy near death which Prince is so familiar with. Prince then concerns herself with a complicated ritual to give Stan the ride of his life. Kai gets suspicious and tests the Xev impostor twice, to see if she kisses like a real Xev. After obtaining the key, she then countermands the order to destroy planet Fire, and directs Lexx to Water. Kai then kills her, and the key flows to a dismayed Stanley.

Lexx 3.05 & 3.06



Lexx 3.05 – Gondola (March 5, 2000)
In a dramatic survival episode, the crippled moth falls to Fire in the night. Duke and Fifi also crash. All of them have to make it to a city before the sun rises, or they’ll fry. The Lexx team: Bunny, Xev, Stan, and the two Kai’s find a wrecked gondola and pump it up. During their flight, they realise that there is not enough fuel to make it across the lava lakes, unless there is less weight. The protoblood Kai volunteers to jump overboard and walk through the lava on foot. Duke decides it’s easier to just to sit in the desert and die, which worries Fifi a bit. Duke explains the Water/Fire reincarnation system. However, the Lexx team find them, and stupidly pick them up, unable to solve the moral dilemma. Bunny gets thrown overboard. Stan and Xev make it to tower of K-Town, and then defend themselves against mortal-Kai

A simple survival story with a twist at the end. Just average (3/5)


Lexx 3.06 – K-Town (March 12, 2000)

On entering K-Town through a hole high in the wall, Xev and Stan have to deal with the tunnels and the demented inhabitants – the most evil of the souls incarnate. They meet some people who enjoy throwing rocks at them. Kai climbs up the tower, finds them, and then has a systems failure. They also meet Mantrid, who is devoid of memory, but highly encouraged by the idea that he is the greatest biovizier who ever lived. He participates in Kai’s diagnostic procedure, does something stupid, and then Kai cleanses him. Xev and Stan manage to throw Kai off the tower to realign him, but it doesn’t work, and he gets captured.

What a mess of story threads that don’t work and make no sense. The re-appearance of Mandrid is illogical and Kai’s ‘undergarment’ is unnecessary and probably belongs in a 1990’s puzzle adventure game. (1/5)


Lexx 3.03 & 3.04



Lexx 3.03 – Gametown

Stanley begins plotting how to destroy the planet Water without alerting Kai and Xev, or steering the starving Lexx. May gets better or worse, depending on his attitude. After waking the moth breeders, Kai goes to Gametown to find some food for Lexx. Gametown is a floating city inhabited with aerobics enthusiasts who play basketball all day. There is one inhabitant who is not quite right: Fifi. He doesn’t play the games by the rules, and he quickly betrays everyone, by stealing all the moths and food, then heading over to Fire, to surrender himself to Duke, so he can destroy Water. Stanley’s attempts on Water are foiled by Xev, who nearly strangles him, then smothers him with her breasts. May ridicules him, and heads off with Prince.

Some interesting plot turns, but undermined by slow pacing and lacking any tension or excitement. The weird thing is that on a mainly water planet, with no sign of land, the food offered is mainly fruits !!
Where is the fish and seafood ?


Lexx 3.04 – Boomtown

Duke and Fifi attack Gametown. They kill everyone he knows and raze the town. Duke likes Fifi. Kai requisitions an attacking moth, and then heads over to Boomtown with Bunny and Xev. All they do in Boomtown is eat and have sex. Stan is thrilled to find a number of the women willing to sleep with him, but Xev isn’t so lucky, as the men have adapted way of avoiding sex by interminable foreplay. Bunny makes several efforts to have sex with Kai, which he finally deterrents only by cutting of his left hand to demonstrate that he is not alive. Back on Fire, May kills Prince in a questionable gambit, then Duke and Fifi decide they’ll paint May and his former deputy with explosive tar, and burn them. Duke and Fifi fly to Boomtown and burn it.

The most frustrating thing about this episode is Xev, for a long time she has complained about lack of sex and showing she can be aggressive when it comes to Stan. But in a situation with a willing male, suddenly she becomes submissive. And the character of Fifi makes no sense at all. Where did he come from and why has he become psycho # 3. Kai’s unwillingness is indulge in sex is strange, given that all of his appendages appear to be working. At least Stan finally gets his way, but why is he wearing a nappy ? Very illogical episode (1/5)



Rules of the Screen

Stolen from the Internet

follow a set of (largely unwritten) rules that have been developed over the last ten years. Uniquely, this article takes a look at both the rules and their basis in psychology.

The elements you see in modern user interfaces (windows, menus, icons, etc) were founded on basic, psychological principles – eg, people are better at recognition than recall.

Psychologists spend their time devising deceptively simple experiments using, as their laboratory equipment, people’s heads. Some of their discoveries do not seem earth-shattering (it is, apparently, harder to remember “The man looked at the sign” than “The fat man looked at the sign warning of thin ice.”) Over time, they have built up a model of the mind that is far from the powerful, flexible superbrain we might think humans possess. Rather, it is quirky, fallible, distracted and often downright cantankerous-more Homer Simpson than Side-Show Bob.

One of the earlier findings was that people are considerably better at recognition than recall. Ask me to describe the icon for ‘set foreground colour to match this’ and I’ll have difficulty, but show me a palette of icons and I’ll pick out the pipette. Or, at least, I will if I’ve used it before. This is the fundamental principle behind both icons and menus: having people choose from a list they’ve seen before is far easier than having them type long strings of ill-remembered commands. Information in the world is easier on users than information in the head. Not just easier, but quicker too; measured in microseconds, recognition beats recall hands down.

Research is ongoing-new techniques and interface ‘widgets’ are introduced with each new operating system release. Some are successful and others die out.

Of course, every application now uses menus and icons, but there is more to it than that. Further research shows that it’s easier to find what you’re looking for when items are sorted into meaningful groups. If that seems obvious, watch someone using menus. They will frequently look in two or more menus before finding what they’re looking for, no matter how many times they’ve seen it before. Are the menus grouped in a way that is meaningful for the user or for the developer? Or for a designer in search of elegant simplicity-one set of menus across different applications, achieved by making their names as bland as possible.

What the user sees…
The key to a successful interface is determining the predominant user type-beginner, intermediate or expert-and considering what users are thinking when they use an application.

Diversity of users is a key problem for the visual interface designer.
Typically, users are segmented into three capability levels: beginner, intermediate and expert. These levels can be applied to three domains: computing in general, a specific operating system and a specific application. You can be an expert Windows user but a beginner at Excel, for instance; or you could be an expert user of your company’s order entry system but oblivious to everything outside it (there are users who believe the order entry system is the computer). ‘Expert’ here means ‘thoroughly familiar with’, rather than the usual sense of ‘world’s leading authority’.

A common mistake is to focus too much on the beginner, forgetting that the user will progress to an intermediate level fairly swiftly and will then be held up by features designed for beginners.

Beginners get a lot of attention, but in fact there are not many of them around, simply because they learn. For the custom business applications we are concerned with, users are almost entirely intermediates learning to become experts since they use the software nearly every day. If you design your interface for beginners, it will quickly be viewed as tiresome by most of its users. Instead, your application should quietly introduce itself and aim to make users intermediates as soon as possible.

Before looking at which interface features favour the different user types, consider what users are thinking when they use an application. Broadly, a user will have one of three questions:

What can I do with this application?
How do I achieve this specific task?
If I rummage around, what will I find?

1) and (3) might seem trivial, but they are enormously important in transforming beginners into intermediates and intermediates into experts. That said, you don’t need to build much direct support for them. The crucial question is (2)-to see why, we need a model.

When you want to do something, say read a book after dark, you go through four steps (what follows is a simplified version of a model introduced by interface design guru Don Norman).

First, you determine a goal; in our example it might be “make it lighter, so I can read.” You then translate the goal into one or more actions such as “get out of the chair and turn on the light” or “ask someone else to turn on the light.”

When the action has been carried out you look for feedback, in this case it gets lighter. Finally you evaluate whether the goal has been achieved.
Users apply a four-step sequence when trying to carry out a task on an application-goal, action, feedback and evaluation.

The channel most appropriate for completing a task varies with the user type: menus cater well for beginners, keyboard short cuts are for experts and the still controversial toolbar is aimed at the largest user group-the intermediates.
That might seem like an awful lot of thinking just to turn on a light, but of course for such simple actions it’s all subconscious. The same goal-action-feedback-evaluation sequence applies to users trying to carry out tasks with your application. Typically, two problem areas arise: my goal is to send a mail message, but how do I do it (the ‘gulf of execution’); and I think I just sent one, but how can I be sure (the ‘gulf of evaluation’)? The first of these is our old friend (2) from the discussion above and is by far the most common, and most serious, interface problem.

When you want to offer your users a way of completing a task, you have four main channels to choose from: menus, the keyboard, a toolbar or direct manipulation with the mouse. For some tasks, such as resizing a window or typing a letter, the choice is obvious (though ibm’s ageing CUA guidelines still insist that everything should be possible from the keyboard—have you ever tried resizing a window from the keyboard?). For commands, though, the choice is menu, keyboard and/or toolbar. Interface gurus agree that menus cater well for beginners and keyboard shortcuts are for experts, but this leaves our main target group, the intermediates. It was for this group that the toolbar was invented.
However, it doesn’t boil down to building an interface exclusively for one user type-it’s more a question of getting the right mix. Inter-mediates will quickly get accustomed to toolbars and accompanying tooltips. This frees menus up to teach beginners.

The argument against toolbars runs like this: they waste screen real estate, the icons are too small to be recognizable and, since users can’t figure out how to customise them, they usually feature the wrong set of commands. The argument in favour is more practical: once people start using a toolbar, they can’t live without them. Microsoft neatly solved the recognisability problem with ‘tooltips’-the label that appears if you hold the mouse over a toolbar icon for a couple of seconds. In fact, if you put the most commonly used commands on a toolbar (preferably customisable, though this can be hard work for developers and users alike) as well as giving them keyboard shortcuts, you have freed your menu bar to do what it does best: teach beginners. Faced with a tight budget, custom software developers often drop niceties like toolbars and right mouse-button shortcuts (the fifth channel). This is a mistake.

There are a number of further aspects to consider when examining command channels-affordance, the way in which an object’s appearance hints at what you can do with it, and pliancy, the way an object highlights itself or produces an entire menu when the pointer moves near it.

Before leaving the important topic of command channels, let’s look at two other aspects, one very old and one new. Direct manipulation (mousing an object) usually involves drag-and-drop. Though drag-and-drop has been around as long as guis, users have trouble with it. The problem seems to be with affordance, the way in which an object’s appearance hints at what you can do with it. In the real world, for instance, handles afford pulling. This makes handles on doors that need pushing pretty annoying (the designer probably thought this was a small price to pay to avoid the ugliness of a metal plate for pushing). Icons of files, just like real world files, do afford ‘physical’ drag-and-drop between folders or into the wastebasket. But chunks of text do not afford dragging to somewhere else in a document—so this should be an optional feature, aimed at experts. The rule is, except where drag-and-drop is clearly an ideal solution (such as rescheduling events in a diary application), avoid making your users do it.

Affordance is also behind a much more recent development: pliancy, or having an object highlight itself when the pointer is moved near it. The buttons in Internet Explorer are a good example of this—they change from subtle monotone to 3D colour whenever the pointer is within clicking distance.

Some objects go further than this, producing whole menus without being clicked (see Microsoft Encarta, for instance). This can be somewhat unnerving at first, but offers both ease-of-use to beginners and speed-of-use to everyone.

For speed users, Apple’s single menu bar is faster than menus mounted on windows. The keyboard, of course, beats both and ones with a Dvorak layout are faster than QWERTY, but only by 10%.

On the subject of speed, here are a couple of other research findings that will be of interest in situations where every microsecond counts (high volume data entry, for example). First, mouse usage.

Fitt’s Law says that the time it takes to click an object is proportional to the distance the pointer has to move and the size of the target. This explains the surprising fact that Apple’s single menu bar is more efficient than Microsoft’s one-per-window paradigm. Apple users need much less accuracy to hit the target: they simply wham the pointer off the top of the screen. In effect, their target is several times larger. (Windows 95 uses the same trick for its Task bar.)

Second, keyboard layout: isn’t it about time we did away with those silly QWERTY keyboards? In fact, an Alpha layout would be no quicker to learn (you might know the alphabet, but that doesn’t help significantly when the sequence is broken into three rows) and actually slower for experts.

The Dvorak layout, based on statistical analysis of key usage, would be fastest, but only 10% better than QWERTY.

The problem with overlapping windows
Overlapping windows were developed during the backlash against character-based terminals. In fact, it is rare that a user needs to view more than one window at once. This fact is exploited by browser-centric applications.

Ever since we had GUIs, we had overlapping windows. There is, of late, a growing feeling that this was a wrong turn in the history of visual interfaces. People are most effective when they are in a state of ‘flow’—ie, focused on a single task without interruption. Having to find a window somewhere behind the front one is an interruption. So is a dialog box or an error message (more of these later).

If you have three sets of papers on your desk, each relating to a different task, you do not put them on top of each other, you arrange them in separate piles and shift your focus from one to the other only when changing tasks. Nor do sequences in movies appear from behind each other and then drop into the background. This just isn’t how your mind works: attention is serial. Tellingly, the most successful application ever, the web browser, uses a serial, single-window idiom.

There are situations where you focus on more than one thing at once: when comparing, say, or copying from one place to another. Which is why overlapping windows work best where they were first applied: file managers like Apple’s Finder.

In those days you could run only one application, so it was difficult to get confused. As PCs became able to run several applications, a slew of interface innovations were thrown at the problem of managing them: Apple’s application menu with Hide and Show, Microsoft’s ALT-TAB and, more recently and most successfully, the Task bar.

For designers of custom applications, the task is somewhat simpler as they can assume that the user concentrates on a single application.

Forcing a user to move between windows and dialogs in the course of completing a single task is at first confusing and then annoying-the activity is surplus to the task.
If you are designing a custom application (other than a small utility), you can make the simplifying assumption that, if a user is working with your application, they are not doing anything else. So use the whole screen. Some gurus go further than this. Alan Cooper (creator of Visual Basic) suggests the following way of thinking about dialog boxes: imagine each window is a different room. If I visited your home and you demanded we move to a different room to shake hands, I would consider that eccentric at first and, pretty soon, downright annoying.

Of course, if we decided to start a new task, such as eating dinner, I would think nothing of moving to the dining room (not that I want to suggest that eating at your place would be a ‘task’).

If your user wants to do something they consider part of the same task, such as change font or view more detail, don’t give them a dialog box, let them do it right there in the window they already have. Reserve dialogs for new goals, such as starting a new search, not new functions. Some applications make you fight through several layers of nested dialogs, which is like finding yourself in the room under the stairs in the cellar just because you asked the time. Still others lure you into a false sense of security with commands like “New Table” which produces, not a table, but a dialog asking you about that table you requested.

There are still a number of common pitfalls designers tend to fall into-boundaries between new tasks, default settings, undo options and poor error messages.

Users will come up with a myriad of task variances which will drive the requirement analyst mad, but in practice users will take the default option 95% of the time. Toolbars are recently starting to get this right.
While many dialogs can be replaced with objects in the main window (on a toolbar, for instance), many more aren’t needed at all. Software designers do not distinguish between the occasional and the frequent: if something happens at all, the application has to cope with it. If you want to wind up a requirements analyst, neglect to tell them something and, when they find out about it, say “well it doesn’t happen very often so I didn’t think it was worth mentioning.” Yet this is how users really think, so when they choose Print, asking them stupid questions such as “where?” and “how many copies?” is annoying. They take the defaults 95% of the time. Print buttons on toolbars have recently started getting this right—they just print. If you really want multiple copies, you go and find the menu entry. A famous dialog in an early version of Excel would appear every time you tried to clear a cell and ask what, exactly, you wanted to get rid of—the contents? or maybe just the formatting? Getting just a little cleverer with defaults (remembering what the user told you last time, for instance) can make a big difference.

All too often designers use error messages as a get out for poor design. With a well designed application, a user sees an error message so rarely that, when they do, they really sit up and take notice.

Some confirmation dialogs and error messages are even worse. Users who have made what psychologists call a slip—deleting the wrong thing, say—will simply confirm the slip when asked. What they need is a way to undo, though this is a notoriously difficult thing to implement. A classic confirmation dialog in an early database application (we couldn’t find a screen shot) said “Continuing may corrupt the database” at which point the user could choose between two buttons, one labelled “Yes” and the other “No.” Kafka-esque error messages like this, many of which are simply unnecessary, seem deliberately worded to offend.

Don Norman’s Six Slips (from The Design of Everyday Things)
Capture errors A frequently performed activity takes over from (captures) the one you intended. For example, driving your car to the supermarket and finding yourself at the office.
Description errors You perform the correct action but on the wrong object due to their similarities. For example, putting your dirty washing into the tumble drier rather than the washing machine.
Data-driven errors The arrival of sensory data triggers an automatic action, and this disrupts an ongoing action sequence. For example, you spill your drink when someone asks you the time.
Associative activation errors Internal events (thoughts) can also trigger automatic actions— eg, you think of something you ought not say, then say it (the classic Freudian slip).
Loss-of-activation errors You are half-way through an action sequence and realise you have no idea why you started. For example, you find yourself walking into the kitchen but have no idea why you are there.
Mode errors A device, say your video recorder, has more than one mode of operation and the same action has different results in different modes. This is probably the most common slip caused by poor visual interface design.

Trying to be helpful

A common problem faced by beginners on their way to intermediate status is information or ‘button’ overload.

A number of UI features have been designed specially for beginners such as help, wizards and tips. For custom business applications our objective with beginners is to make them intermediates. Training courses, whilst efficient, are quickly forgotten. What is needed is ‘Just In Time’ training.

Keeping in line with a person’s natural learning process-declarative then procedural knowledge phases-a ‘Just in Time’ training method supports the user’s progression from beginner to intermediate far more effectively.

When faced with a new environment, people perceive its complexity to be higher the more buttons there are to press. This is why the ‘simplest’ telephones have just the digits 0-9, *, # and ‘R’. They are, of course, almost impossible to use. The easiest interface, which would ironically be perceived as horribly complex, would be one button per function. On screen, the designer is able to hide functions until they are needed (depending on the user’s current task, for example) so there is no excuse for overloading buttons with several functions.

After overcoming their initial impression, people first pick up declarative knowledge—a real world example would be what a bicycle is and the parts it is made of. Only later does their knowledge become procedural—how to ride a bike ‘without thinking’. Beginners have to plod through each step; experts rely on subconscious (and much faster) procedural knowledge.
Help has also evolved from being a mere reference tool to a more active task orientated search function.

Help, which has been around for ever, has only recently become helpful. This is a result of a move away from pure reference help (mainly declarative) and a new focus on how to achieve specific tasks (much easier to make procedural). Some help is now ‘active’ in the sense that it will take actions for you, such as opening a control panel, if asked. Since this makes for a fast payoff, users who previously thought help was for dummies will now make the investment when they are stuck.

Tips (shortcuts suggested by the software, often as a result of watching what you are doing) and tool tips are further examples of the blurring boundary between functionality and help. The trend is towards help that is ‘in your face’-a trend that is being accelerated by the World Wide Web for two reasons: the search idiom is becoming ingrained (so searching for help is too) and applications are decomposing into applets so users will need guidance to fit them back together.

Also classified as ‘active help’ are wizards and, although they take the user through the whole task quite simply, they do little to teach him how to complete the task himself.

Wizards are another example of active help, though these bring problems. Using a wizard, you quickly complete a task but you learn little about how. If anything, you are left more impressed by the mystery of it all. This makes wizards good for situations where learning is not the objective: infrequent tasks, say, or infrequent users. Over-reliance on wizards has resulted in some lazy design.

The processes by which these rules of the screen are reached are not laid out or even chronological for that matter. They are, more often than not, found by trial and error, with the outcome confirmed or refuted once the user gets his hands on the application.

In case you think that any of this is obvious, you should bear in mind that grown adults have spent days arguing over such things as whether there should even be a right mouse-button, let alone when to use it. The argument is now irrelevant, of course, since 95% of users have one. This is typical of how user interface progresses: gurus pontificate, academics research (into technology on which they get educational discount rather than technology everyone else is using) and try to prove ideas that are already out of date, developers try their best to follow the written guidelines and a vendor, usually Microsoft or Apple, makes the whole lot irrelevant by introducing an innovation which users, voting with their fingers, make or break overnight. Someone then quietly rewrites the guidelines to fit. This is the context in which designers work. If you have a serious yearning to invent UI rather than apply it well, you should move to the West coast.