The LED block gave me an idea for how a piston could work in boundless.
Separate out all the power stuff. No levers or switches. This would have 8 “states” (nine if you include “off”). Use a chisel to select between them.
The piston would be one block in shape when compressed or “Closed”.
State
1 - Off
2 - One block extend, constant in-and-out motion
3 - Two block extend, constant in-and-out motion
4 - One block extend, “Closed” resting state, “OUT” motion when stood on
5 - Two block extend, “Closed” resting state, “OUT” motion when stood on
6 - One block extend, “Open” resting state, “IN” motion when stood on
7 - Two block extend, “Open” resting state, “IN” motion when stood on
8 - One block extend, “Closed” resting state, “Flipper OUT” motion when stood on
9 - Two block extend, “Closed” resting state, “Flipper OUT” motion when stood on
Stacked piston blocks would all copy the inputs and state of the top one.