I never considered that the backplane is the same height as the inter dot distance. I thing I can think of as a possible improvement would be to put the single dot side ways, and put a grain of salt on each side. Or find a very slight indentation to put it in.

I really like the thinking of moving the smallest piece to the very bottom!

This would make a great quiz night team challenge or corporate team-building activity.

One of the conditions was that it should be able to stand on its own ('freestanding'), that one can't balance on the lower piece.