Simulates liquid pouring through a porous material (like water through coffee grounds or oil through rock).
If the porosity (probability of a cell being open) is above a critical threshold (~0.5927 for site percolation on a 2D square lattice), the liquid will reliably reach the bottom. In this ASCII version, cyan (`#76c7d5`) represents the flowing liquid (`~`), dark green (`#394034`) is solid rock (`#`), and empty space is black (` `).