Candle Movers - Robots show emergent behaviour

Candle movers is an artificial life simulation of a robotics experiment by R. Pfeifer, Uni Zurich.
The simulated world is a rectangular area that is filled with candles (red dots). A couple of animated robots (green dots) move through the area and will shift the candles. Each robot may shift up to a maximum number of candles. If this number is exceeded, it leaves the candles alone and moves away in a randomly chosen direction. That's all of the rules.
When the world and its interactions get simulated, you will get to see an emergent scenario that is not easily derivable from the simple elementary rules. See for yourself.

'Candle Movers' as a Java Applet

'Candle Movers' for Android devices