This video I found while trawling through Computerlove - apparently it’s old and may well have been posted elsewhere, but when has that ever been a concern? I’ve never seen it before today, so I’m going to put it here. So there.
I like the shapes that form different letters depending on which way you look at them. I wonder if you could have a set of shapes that each show different characters (say, from three directions) with no repetition? It’d be tricky, especially if you restricted it all to one typeface… Even if not, I wouldn’t mind a couple of the ones in the video, just to play with, you know?