Each half of the puzzle includes two mazes, one on top of the other. The mazes are separated by an acrylic layer with a single hole for the ball to pass through. Once you`ve navigated the ball through the upper maze, it drops through the hole to the next layer. Furthermore, the two halves of the puzzle are connected by gears such that rotating one half of the puzzle also causes the other half to rotate. In order to solve the puzzle and remove the two balls simultaneously, all four mazes must therefore be completed at the same time, making for a very tricky puzzle.