Applications for using a single pushbutton to advance a circuit to its next logical state are legion. Typically, there are just “on” and “off” states, but there can be more. The heart of the circuit ...

Toggle, slide, push-pull, push-push, tactile, rotary, etc. The list of available switch styles goes on and on (and off?). Naturally, as mechanical complexity goes up, so (generally) does price. Hence ...