A mechanical system with two noncircular pulleys in a differential arrangement is demonstrated in this video. It is able to convert the force from a linear spring into a balancing torque for a rotating payload. Using this system, the payload is essentially floating in space as gravity is cancelled by the mechanism over a full rotation of 360 degrees, a technique known as static balancing. Antigravity courtesy of mechanical engineering!

For more technical details, see:
"Differential Noncircular Pulleys for Cable Robots and Static Balancing", by Dmitri Fedorov and Lionel Birglen, ASME Journal of Mechanisms Robotics, 10(6), 061001 (Sep 07, 2018), DOI: 10.1115/1.4041213
Link: http://mechanismsrobotics.asmedigital...

Soundtrack: By the Coast (2004) by Antony Raijekov, licensed under CC BYNCSA 4.0.