A brass driver gear (42 teeth) meshes a chain of six gears. Where teeth mesh, the linear speed at the pitch circle must match, so each gear's angular speed ω is inversely proportional to its own tooth count: ωi = ω0 · T0/Ti. Every meshed neighbor spins the opposite direction. Two of the larger gears carry off-axis (eccentric) cams; as a cam rotates, its center traces a circle of radius e, and the follower piston's position along its cylinder axis is e·cos(θ) — the same crank-slider conversion a real steam engine uses to turn rotation into a back-and-forth stroke. A timer independent of gear speed vents a puff of steam from the pipework at fixed intervals.