Clock 18 is an experiment with alternative force laws. In this universe, spacetime is made up of three space-like dimensions and one time-like dimension. I'm given to understand that were all dimensions space-like, different physics would prevail, and what we think of as charged particles would have oscillating fields. In this clock, such oscillating fields are simulated, mediating between the trace particles and between the trace particles and the clock hands.
For an entire fictional examination of the implications of 4 space-like dimensions, see the excellent Orthogonal Series, by Greg Egan.