Toom Ising
Each square is a spin (black = up, white = down).
Each Monte Carlo step attempts a single-spin flip, chosen uniformly at random,
accepted with probability min(1, exp(-ΔE/T)) under Glauber/Metropolis dynamics.
The selfish energy has coupling J_E to the East and J_W to the West, and coupling 1 to the North and South.