Quantum computing uses qbits which have complex- valued probability distributions. Computer simulations of quantum processes are widely known to exist. I propose building an "abacus" which mechanically simulates qbits. Specifically, one small part of the probability amplitude of a qbit would be mechanically simulated using a car tire with a weight attached. The amplitude is represented by the momentum of the car tire, and the phase is represented by the angular position. By adjusting the weight and speed (filling the tire with some amount of sand and then spinning it up with an electric motor) the initial state of one small part of the qbit probability amplitude is programmed. Many such tires would be arranged on a shaft, resembling a giant spinning treaded kebab, to mechanically approximate a single qbit. To add qbits, two such spinning tire kebabs would be brought into contact such that they begin spinning at the same speed. To measure the state of the qbit, measure the mass and velocity of one tire at random.-- sninctown, Nov 05 2020 This sounds more like an art installation than a meaningful simulation, but it might find a place in a Science Discovery Centre or the like, so we will award a bun - pending a critique by [xenzag].-- 8th of 7, Nov 05 2020 random, halfbakery