Have all keys perform trigger a certain function (which changes after each keypress) when pressed.
This! When keypressed, do x. Next time keypressed, do y. etc. (I thought this would work by removing the keyboardlistener once each function is performed, but nope. Instead, now when key is pressed, it performs all functions connected to keyboard listeners at the same time, resulting in chaos.

It's a (very simple) game for tiny kids (tots) ... they don't know to press "shift" or "left" or "right", so I have to make possible for them to bang on anything on the keyboard and get a result.

But I can't find ANYTHING out there that refers to this concept.