[ydxlyeud] Hilbert curve maze

turn a Hilbert curve into a unicursal maze: this is easy, a no-op.

a bit fancier: index each point on the curve by its arc length from the start.  mark on the walls of the maze the index of what's on the other side of the wall.  or, color walls by the difference of indices.

Hilbert curve never goes straight more than two steps in a row.  are there nice space filling curves on a grid that aren't so constantly curvy?

Mr. Bones's Wild Ride; Mr. Hilbert's Wild Ride: each time you think you are nearing the end, you are actually only a quarter of the way through.