lifetime:

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A platform with a lever. The lever can be moved in a cone and rotated. A tractor brings it back to its neutral position.

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A grabbable door with a hinge between it and world-space.

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A chain of blocks connected by hinges.

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The block can only move up and down over a range of 1/2 meter.

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A chain of blocks connected by slider constraints.

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A chain of spheres connected by ball-and-socket joints between the spheres.

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A chain of spheres connected by ball-and-socket joints coincident-with the spheres.

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A self-righting ragdoll. The head is on a weak tractor vs the body.