Objective

A tin skater circles the pond inside a wound-up snow globe. Every beat of the music box lays a bright rung across the ice, and some rungs carry a brass pin. Tap to hop: one tap is one committed arc, 0.80 s long and 2.05 units high, and a tap thrown in mid-air is ignored.

Scoring

Every pin you clear is one beat kept. A lamp hanging at the top of the arc is worth three more.

The wind-up

The pins grow from 0.75 to 1.45 units tall over the first 29 seconds, the tempo tightens from 0.95 s to 0.60 s a beat, and the rests between pins shrink from as many as four beats to two. Early on you can hop every rung and survive. Once a beat is shorter than the hop, a hop spent on an empty rung lands you late for the next pin, so you have to read which rung is loaded.