A troll sits in a ring of seven platforms. Each platform contains a Towers of Hanoi puzzle. At midnight, the troll moves one tile in each puzzle. Five times a year, one of the puzzles is solved, revealing a stack of 9 tiles on a single tower.

The user may preview what happens at midnight by swiping left or right to move forward or backward one day or up or down to move forward or backward 73 days. Users may wish to see what happens with multiples of 73 days.

If a user double-taps, today's date is displayed.