Factory Balls 2, an online logic game, uses virtual ping-pong balls and challenges you to duplicate patterns. You are shown a picture of a ball decorated with a design. You are given a number of tools such as buckets of paint, belts, sunglasses, seeds, water and spray paint. The object of the game is for you to reproduce the pattern by determining the correct sequence of steps and the correct tools.
The ping pong balls initially are white. Their surface must retain paint in a uniform fashion. They must be able to have seeds applied to them such that they do not wash away when you apply water. The surface must be stiff enough so that it does not flex when a belt is wrapped tightly around the circumference; and, yet stretchy enough that the suction of a plunger will cause a local protrusion.
The balls have a diameter of 37 pixels and have shadow effects that give the ball a 3-D appearance.
References: http://www.mathplayground.com/logic_factoryballs2.html