Planetary gearbox

Sun + 3 planets + ring + carrier. Watch the planets spin on their own axes while revolving around the fixed ring at exactly the right ratio.

gear reduction

Quadcopter drone

X-pattern four-rotor drone hovering and pitching in place. Adjacent props spin opposite directions so the body torques cancel.

hover + spin

Geneva drive

Continuous rotation in, intermittent 90° steps out. The classical film-projector indexer in 4-slot form, with the lock plate visibly holding the cross between strokes.

intermittent motion

Bicycle

Crank + chainring + chain + cog + wheel drivetrain. Pedaling drives the rear wheel; the bike rolls forward without slipping.

forward motion

Robotic arm

5-DOF articulated arm with a parallel-jaw gripper. The trajectory parameter blends every joint through a smooth choreographed sweep; flip the override switch to drive each axis by hand.

forward kinematics

Solar system

Mercury → Saturn orbiting the Sun at roughly Keplerian speed ratios. Earth carries its Moon along through a tiny kinematic chain.

orbital mechanics