The Road More Traveled #8

I shall be telling this with a sigh
Somewhere ages and ages hence:
Two roads diverged in a wood, and I—
I took the one more traveled by,
A hash then made all the difference
~ Robert Frost (very nearly)

In these woods paths each begin from a single source. Individuals start at that source and branch outwards.
At each branching step, an individual may elect to go in any available direction, but has a bias towards paths that have been more heavily traveled previously.
Paths are shaded according to how much traffic they've received.
Obstacles may be added, resulting in distinctive growth patterns.

Features
grid mode: In which directions can we branch
arrangement: Where are paths and obstacles situated
palette: What colors are used
lighting: Light mode or dark mode

Keyboard:
'a': Animate your creation
'l': Toggle light mode