that's how it's currently implemented
now that #
is free again, I could make that the depth operator
I noticed that I overlooked one relevant junction: a straight corridor where you're looking at the wall. that is, there's a neighbour to the left, one to the right, but neither straight ahead or at your back
this can only happen with very specific grid rotation setups
I've decided to keep the normal left/right with negative/positive switch. but if the value is 0, the direction is chosen uniformly at random. that gives a weird, cumbersome, but usable built-in PRNG.
I've already used it to build a random byte generator.