Drawing / Paper / Sketch
For educational purposes, I believe that at some point we all need a paper medium to be able to express the geometry of a possible solution with all the details that can be created with a sketch in hand … and not with the board.
Also, when you are in transport, it is impossible to play on the set, but you still have ideas coming up
And for very complex solutions, I think that’s the only way to figure it out, much faster than the board.
So here is my idea of a paper base. You can print it and draw on it.
Enjoy - Thomas