The grey linkage horse on its red stand on a walnut desk between an open laptop and a white mug

Mechanical horse walker

One turning shaft, four Jansen legs, a head that nods and a tail that swings with every step.

A turning shaft becomes a walk.

It starts under the body.

The drive sits here, below the gears. Give the wheel on either side of the horse a turn by hand and every part after it moves with it.

Two turns in, one turn out.

A 12-tooth bevel standing on end meshes with a 24-tooth bevel on the crank line: two turns of the small one for every turn of the crank.

Two crank pins, half a turn apart.

The crank line runs across the body to a wheel at each side, each with a pin set off its centre. Each side of the horse hangs its two legs on one pin, so one side lifts while the other pushes.

A circle in, a stride out.

Every leg is Theo Jansen's linkage, two triangles and four rods. The pin only goes round; the hoof follows the sand line, flat along the bottom for the push and lifted for the return, a step 2.7 in long.

Four legs, taking turns.

The foreleg and hind leg on a side share one pin and reach in opposite directions; the far side runs half a turn behind. Some hooves always push while the rest swing forward.

The head nods with every step.

A second, smaller wheel on the crank line pushes a rod up into the neck, which rocks through about 21° on its pin at the withers. A bar along the back passes the same rock to the tail.

Walking in place.

The red stand holds the body up, so the hooves swing 0.7 in clear of the desk. The horse walks on the spot for as long as you keep turning.

Up close.

7.9 in tall and 5.4 oz. The whole horse is light grey PLA, an open frame of rods and pins you can see straight through, on a red stand that keeps it off the desk.

The horse walker on a wooden kitchen table in morning light, a glass of orange juice beside it
Next to a breakfast glass it stands about twice as tall, and it takes less of the table than a plate.
Close view from above into the body: the toothed bevel wheel on the crank line, the shaft collars and the back bar over them
Look down through the back and you can watch the bevel wheel turn the crank line.
Two hands holding the horse walker by its red stand at chest height in a bright room
It lifts by the stand with two hands, and the whole thing weighs 5.4 oz.

Its walk, frame by frame.

Eight moments in one turn of the crank, drawn from the leg geometry itself. The near side is solid and the far side faint. The sand line is the hoof's path, which shows the trick of a Jansen leg: a long, nearly flat stroke along the ground, then a high lift back.

    Stride
    2.7 in per step
    Hoof lift
    1.6 in on the return
    Jansen's lengths kept
    11 of 13
    Head nod
    about 21°
    Three-quarter view from the tail end: both pairs of legs at different points of the step, head raised beyond
    Stopped mid-turn: the two sides sit half a step apart.

    One horse, one stand.

    Mechanical horse walker: a Jansen walker you can watch work.

    1
    walking horse with 4 Jansen legs, a nodding head and a swinging tail
    1
    red stand that holds it clear of the desk
    Size
    7.9 × 4.6 × 7.9 in (long × wide × tall)
    Weight
    5.4 oz
    Material
    PLA, light grey horse, red stand
    Legs
    4 Jansen linkages on one crank line
    Drive
    by hand, at the wheel on either side; 12- to 24-tooth bevel pair
    Moves
    legs walk, head nods, tail swings
    Stride
    2.7 in
    From behind and to one side: the tail, two hind legs reaching back, the gearbox block and the red stand under the body

    Good to know

    What makes it move?
    You do. Turn the wheel on either side of the body and the crank line drives all 4 legs, the head and the tail at once. There is no motor and no battery.
    Does it walk across the table?
    It walks in place. The red stand holds the body up so the hooves swing 0.7 in above the surface, and you watch the gait without chasing it.
    What is a Jansen linkage?
    The leg Theo Jansen designed for his walking sculptures: two triangles and four rods that turn a crank pin's circle into a hoof path with a flat bottom. This horse keeps 11 of his 13 lengths exactly.
    What is it made of?
    PLA plastic: light grey for the horse and its linkage, red for the stand. It weighs 5.4 oz.
    How big is it?
    7.9 × 4.6 × 7.9 in, long by wide by tall, stand included. It fits on a desk beside a keyboard or on a bookshelf.