Runner

The simple setup: a point runs straight across the canvas until it hits either the frame or crosses its own tail - and gets reflected off into a slightly different direction - in the sketch above it changes direction randomly in the range of -10..10 degrees.

The video on the left shows a speeding up capture of the above 'live' version, the video on the right shows the results when no deletion of the tracks happens - but the runner color changes when the picture is mainly black.



The below picture shows the results varying the maximal random deflection angle (from the top 1, 2, ... 15, 20, 25, ... 90) after different points in time (left to right). As can be seen, for higher deflection angles the runner can get 'stuck' and bounce in place for a very long time.