Mazes are almost entierly context-free. The mazes of `walkinthepark` have no entrance or exit. Not all of them are solvable. Any resemblance to reality is pure coincidence.

All features are distributed equally:
- weave - The internal pattern of sub-mazes.
- density - The density of the sub-mazes.
- color - Yep.
- aim - How big the biggest sub-maze can get.
- bars - How connected sub-mazes are.
- stroke - The randomness of lines.
- skew - How much some sub-mazes are rotated.
- grain - How many sub-mazes are rotated.

@balidani, Dec 2021