A troll sits in the center of this arrangement. At midnight each night, he looks at each platform, in turn and moves tiles according to the rules of the Towers of Hanoi puzzle. Since trolls have very little brain, there is a simple rule that he uses to ensure the right tile is moved.

Black tiles are always moved toward the center. Brown tiles are always moved away from the center. If such a move causes the tile to move off the platform, it is moved to the spot on the other end of the platform.

The troll always moves the largest tile that can be moved with the above restrictions.

Following this procedure, a Tower of Hanoi puzzle is solved 5 times a year, equally spaced, with one occurring on the spring equinox. On the spring equinox alignment, the sun is aligned with the north edges of the tiles.