How do we want to handle multiple pin objects being created for the same physical pin?

[metasoarous]

It's conceivable this could be useful, but could also cause havoc if two different pin instances point to the same physical pin but have different modes, weirdness might ensue. Also, philosophically, it might make more sense for pin abstractions to be inherently stateful, and singletons. This could be accomplished by having the boards enforce singleton pin instances. However, it's also possible that even having pin objects is a leaky abstraction; maybe it's simpler just to focus on board objects and their collective state? Could always rename as board-ctrl...