Diffusion-Limited Aggregation (DLA)

DLA is a process where particles undergoing random walk (Brownian motion) cluster together to form highly branched, fractal structures.
In this simulation, a seed (#) is placed in the center. Particles (.) wander randomly across the grid. If a wandering particle touches an existing part of the structure, it sticks and becomes permanently attached.
This simple local rule gives rise to complex, organic-looking patterns resembling lightning, snowflakes, corals, or root systems.