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Outsider art (aka “art brut“) is an interesting concept: An “artist” performs art without any intention to be awarded recognition or even without telling any other person about his works.

Often this is done by “mentally ill” patients (… although it’s always interesting to think about who/what is normal anyways, whether this is necessarily positive, and who has the right to declare others to be “mentally ill” …). E.g., a person might draw hundreds and hundreds of abstract “faces” of Japanese metro trains. Or another person might lead a “normal” life, draw hundreds of paintings, and these are only discovered after his death.

This level of obsession leads to an unusual intensity of the piece of art, especially if you know a bit about the history of a given “artist”.

To get a quick glimpse at this art, you can run a Google image search. But it is far more interesting to actually go to the musée de la Collection de l’art brut in Lausanne. They currently have an exhibition about Japanese outsider art and they have lots of videos showing the life and the work of each artist.

On my own, it probably would have taken me at least a few more months to discover this museum, but fortunately I had visitors from the hospitality club, which I could accompany to this museum. It is honestly always an honor and a pleasure to welcome such visitors to my place.

If you don’t know what the Hospitality Club is, then you’ve never spoken to me for more than 10 minutes. So I’ll just state without explanation that I spent two nights at Jan’s place in Würzburg, although I had never met Jan before in my whole life.

To me this was both an inspirational, but also an educational stay. In particular, I finally “understood” parkour. Once before somebody had told me about this sport, or rather attitude, but I don’t remember who and in which circumstances. So, although I still knew the name and I later remembered a few details, it was still essentially new to me.

Anyways. Parkour. A “sport” invented in France by David Belle. A sport without any competitions or formally organized structure. More of an attitude. More of an art. Be free. Escape. Have a strong mind. Have a strong body. In other words: Yamakasi. Probably best explained by watching a video.

I always enjoy exceptions to the rules of common wisdom or traditional thinking.

Last weekend I attended a wedding party. So far nothing unusual (though for me this was only the second wedding within the last 16 years). I only knew the bride and nobody else. So far still nothing too unusual. The thing which did not agree with common wisdom and traditions at all was that I had only met the bride once (!) in my life for about four hours two years ago.

I feel extremely honored that I was still invited, even though this was not an enormously huge celebration (< 60 people). I’m also extremely happy that things like this can happen in life, that some people you simply find inspiring and stay in touch.

Tit-for-tat was beaten in the iterated prisoner’s dilemma tournament in 2005 and I only found about this now!

THE example of game theory in a nutshell:

“Two suspects, A and B, are arrested by the police. The police have insufficient evidence for a conviction, and, having separated both prisoners, visit each of them to offer the same deal: if one testifies for the prosecution against the other and the other remains silent, the betrayer goes free and the silent accomplice receives the full 10-year sentence. If both remain silent, both prisoners are sentenced to only six months in jail for a minor charge. If each betrays the other, each receives a five-year sentence. Each prisoner must make the choice of whether to betray the other or to remain silent. However, neither prisoner knows for sure what choice the other prisoner will make. So this dilemma poses the question: How should the prisoners act?”

The dilemma:

1. If you’re one of the prisoner’s it is always “best” (in the sense of a short prison sentence) for you to betray the other person, regardless of how this person behaves.

2. This holds by symmetry for the other person too.

3. If both people act “rationally” they will  both go to jail for 5 years. Quite a lot.

4. If they both act “nicely” (and count on the other’s co-operation) they’ll be free after 6 months. Not a lot.

5. So you’ll think: Ah, so they co-operate! – Not so fast! If person A knows/assumes that person B will be nice, he has no reason to be nice himself. Unless he’s afraid of  person’s B big brother or some other form of retaliation. For a “single round” of “this game” you simply cannot “rationally” justify co-operative behavior.

But this is different, if we “play repeatedly”! Then I need your good will for the future rounds.
Suppose it’s not about serving time in prison, but about getting points, the more points the better.

If both confess, both get only 1 point.  If both co-operate (= shut up), both get 3 points. If one confesses/defects and the other co-operates/shuts up, then the person who confesses will get 5 points, the person who remained silent will get 0 points.

So now we play this game repeatedly. Then I suddenly need your co-operation in several rounds. If I betray you now, I might get 5 points, but then you’ll probably betray me in the next rounds, and I won’t be able to get more than 1 point anymore.

Funny thing: This reasoning only works, if the number of rounds is unknown!

If we know in advance that we’ll play, say, 10 rounds, then I know that in the last round you have no reason to co-operate with me. Hence, I already have no reason to be nice to you in the 9th round, as in the next round you can do what you want anyways (as there is “no tomorrow”). So neither me nor you will co-operate in the 9th round either. But then, why co-operate in the 8th round? Etc…

So this game is only fun to play, if you don’t know the number of rounds in advance, and this is exactly what was done in this tournament (where computer programs were the players/prisoners).

Ok, if you’ve followed so far, just stay with me a bit longer and you’ll get the punchline.

In this tournament, where any super complicated way of choosing to defect or to co-operate could participate, the winning strategy (i.e., the one which accumulated the most points accumulated in a number of “matches”) was a very simple one: tit-for-tat!

You start by co-operating, i.e., by playing nicely. Then you do whatever the other player did in the last move.

This is the Cold War kind of strategy: I start by not dropping by my nukes. If you didn’t drop your nukes last week, then I won’t drop my nukes this week.

Tit-for-tat … unbeaten for 20 years … fascinating … at least for a computer geek!  🙂

Finally, it was beaten 3 years ago!

But, it took a very cleverly choreographed group of 60 players to beat it. These players had some designated “slaves” and “masters”. The slaves would always sacrifice themselves when playing against one of the masters, but the slaves would be always defecting when playing against outsiders, whereas the masters would play a tit-for-tat in those cases. The really clever thing: The rules of the game usually do not leave any room for “communication”, i.e., I can’t simply tell you “Hey, I’m also in your group!”. So the program always sacrificed the first 10 moves to “communicate” through its decisions about defection or co-operation (think ‘handshake‘ if you’re a nerd).

Pretty clever, but ultimately it still seems that as an individual strategy the tit-for-tat performs best.

Optical illusions work because our brain “expects” certain patterns (e.g., that things further away get smaller etc.).

I wonder if through constant exposure to non-standard visual impressions you can teach a newborn child not to “expect” such patterns and hence become “blind” to optical illusions as it would simply see things the way they are (whether it may be parallel lines or of the same level of darkness).
Suppose you have posters of optical illusions on the walls, suppose you try to have as many things as possible upside-down, suppose you live in a room/house with lots of strange optical properties e.g., no angles at 90° and lines on the floor/walls which only make sense/fit together when viewed from one particular position), would this change your way of “seeing”?

Maybe for a specific type of illusion this could work. At least I have the impression that as a child I learned to toggle faster and faster between the alternative realities in pictures such as this one or this one, even when I had not seen the particular picture before.

Later edit: I just came across this hilarious “optical illusion”  😉

One of Maurits Cornelis Escher’s most famous drawings is the staircase which seems to lead higher and higher and higher (or lower and lower and lower … depending on your frame of mind). I very recently learned (by reading in my favorite book) that a similar illusion exists in music under the name of Shepard scale. The effect is best experienced by listening to it (this is an .ogg file, but you can play it directly on the Wikipedia page if you have Java installed). The pitch of the tone seems to descend further and further and further … though ultimately it doesn’t get anywhere. I wonder if anybody can actually create this illusion on a piano. (This would require being able to differentiate between very fine nuances of volume.)

This video gives a related optical experience of zooming in closer and closer and closer, without really getting any closer.

Here’s another audio example where a rhythm appears to get faster and faster and faster (… but actually doesn’t).

Now I wonder: which senses does this work for? Could one construct a set of tastes so that each one appears to be sweeter than the last, although the set is actually periodic? Can one give a tactile sensation of more and more weight though, again, things keep getting back to where they started?


It’s really amazing how many simple but fascinating thoughts have never crossed my mind so far. Take e.g. the issue of free will. As pretty much any philosophical issue it’s first of all a question of definition. Probably something along the line of “being able to make choices” comes to mind.

But which of the following systems/things (if any) can actually make choices:

A ball rolling down a bumpy road, a pocket calculator computing the digits of the square root of 2 one after another, a robot in a T-maze (just a single intersection where the robot can turn left or right), a chess program.

It’s actually not as trivial to tell as one might think. At least not if one honestly thinks about it for more than just a split second. “Repeatability” partly comes into it (so that you can verify that the same system would have behaved the same/differently in the same setup). The difference between randomness and choice is also not completely trivial. Somehow, there needs to be a “conscious” decision. But how can you detect consciousness from the outside without introducing a cultural bias (… it has to “think” just like you …)? It also depends on details such as if the chess program “learns” from its past mistakes. The funny thing with many of these phenomena is that when you become very concrete/specific and give very strict conditions on what it means to have a “free will” then suddenly even certain computer programs (maybe using some random sources) have free will, but then you realize this is actually not what you meant by “free will”.

Every day I wonder more and more where this whole “self” which believes to have a “free will” comes from.

I don’t really care about car racing. But the DARPA recently held a rather different kind of “car race” which every nerd simply has to love: The DARPA Urban Challenge

“Vehicles competing in the Urban Challenge will have to think like human drivers and continually make split-second decisions to avoid moving vehicles, including robotic vehicles without drivers, and operate safely on the course. The urban setting adds considerable complexity to the challenge faced by the robotic vehicles, and replicates the environments where many of today’s military missions are conducted.”

Can a robot car obey traffic rules? Can a robot car parallel park?

Watch the official video (27MB) or try your luck on youtube to find out.

Needless to say that the DARPA probably cares less about traffic rules than about building fully automated killing machines.

Suppose you wrap a (fairly long) rope tightly around the earth’s equator. Now you insert one meter of additional rope and you evenly lift the rope of the earth’s surface. By how much (roughly) will it lift of the ground? 1 micrometer? 1 millimeter? 1 decimeter? 1 meter?

Most people will guess something between a micrometer and a millimeter. Others will first ask for the circumference of the earth (about 40,000 km). But the answer is quite counter-intuitive.

If you ask people directly what the relation between the radius and the circumference of a circle is many will know that U=2*pi*r, or alternatively r=U/(2*pi). But not so many will have the immediate (trivial) intuition that this means that if you increase the circumference by x, the radius will increase by x/(2*pi), regardless of the radius or the circumference. So the rope will be lifted off the ground by roughly 16 cm (~ 1m/(2*pi)), which is also the radius of a circle you’d get by simply taking the one meter of rope and making a nice symmetric loop out of it.

I still find this very strange, even though it’s completely trivial.


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