To complete the game, students must be able to convert the rotation rate given for each ring into a number of complete clock cycles before it is again aligned to the starting point (since that is the only point at which the ship can be launched). Because the game starts with a single ring, the basic calculation can be learned before there is any need to combine calculations and find a common multiple. More difficult rates are held back until the later rings.

(Shift-start will go straight to the last level)

Star image courtesy Pauline Moss.