Its surface is not smooth, unlike the wooden and stone balls, and so its movement is slightly variable. Furthermore, rolling a stone ball through a bridge made of planks will make the bridge collapse. The stone ball is extremely heavy, and can be accidentally rolled off an edge very easily, but this ball can easily push down boxes and bridges. The player initially launches into and leaves all levels with a wooden ball.
The wooden ball is very stable and can be used for several puzzles in the game. It can be transformed into a wood, stone, or paper ball. In the game, the player can change the ball's material with special transformers throughout the game's 13 levels (12 levels originally another downloadable level, level 13 'Speed', is available on the developer's homepage).
