Two turns, one full orbit. The crank's offset pin turns a small drive gear that meshes with the larger crown gear fixed to the wheel behind it. Two full crank turns spin the wheel once around, carrying the captive ball along the rim track and back through the fixed, C-shaped mouth bracket standing in its path.

Every gear, spoke and panel included. Every piece pins or meshes into place: a flat rectangular base, two upright support panels, a hand crank with an offset pin, a small drive gear, a crown gear, the wheel rim with its radial support rods, a fixed C-shaped mouth bracket, and the captive ball. Panels pin into the base, shafts pass through pinned bores, and the ball rides captive between the rim and its track.

Stands about 7.9 inches tall. Run a finger along the rim and feel the fine layer lines wrapped in tight rings. The wheel stands about 7.9 inches tall on a base just 3.2 inches deep, made in PETG at 0.4 pounds, with precise seams where the shafts pass through the support panels.