Tumble

drag it. add corners until it stops lurching.

three chalk shapes on a slate: drag one and it lurches corner to corner; tap it to add sides until it rolls like a wheel

A rolling shape pivots on its touching corner, its centre always one radius away, so it climbs over each corner and drops onto the next edge. More sides make a smaller drop: half a radius for a triangle, almost none for twelve sides, none for a circle.

its centre stays one radius from the corner it stands on. more corners, less to climb.

Concepts: geometry, motion.

An interactive you play with one thumb, on Wundr.