For a puzzle with only two controls (rotate left or rotate right), the HexaRoll puzzle is surprisingly challenging.
The applet was produced in response to a challenge from Andrea.
The original puzzle design is © copyright M. Oskar van Deventer, 2001 and was encoded as applet parameters by Andrea.
The object (in this rendering) is to get the red ball into the yellow hexagon. Just press the rotate buttons. Whenever the ball is free to fall, it will. That's all.
and here's another designed by Andrea. It's allegedly simpler.