Interesting Mechanical Illusion

3-Second Blueprint (English)

1. Eight dots each slide back and forth in a straight line yet collectively appear to roll around a dial as a circle.
2. Under the solid panel, magnets sit on the pitch circle of a 30-tooth gear rolling inside a fixed 60-tooth ring gear.
3. Forward orbital roll and backward spin cancel lateral motion in this 1:2 Tusi couple, producing pure linear paths.