A simple sketch that paints a dot on the trail that goes in circles. The dot has a configurable length trail (between 0 and 6 effectively) and continuously changes color.

There is a configurable one in 'number' chance for the running dot to change direction. Whenever this happens, a persistent dot is painted on the strip just in front of the trail (as if it had collided). The trail pauses for a moment before continuing in the other direction.