I have a Mendocino motor, a toy with magnets, solar panels, and coils. Such a thing requires careful balancing (eg. with tiny bits of tape) to achieve sufficient balance that it will start rotating just from normal light (as opposed to the direct beam of a flashlight).
I cannot balance the rotor so that it will rest in any position (I don't think that's reasonably possible outside of a lab), but it is fairly close -- in fact, it will come to rest in two opposing positions.
My request is this: Please explain to me the physics and/or geometry of why it's possible to have two balance positions? Assume that, outside of sufficient light, there should be a negligible magnetic effect between the coils and the center magnet.