Equation: phi_tt = laplacian(phi) - m^2 phi - lambda phi^3 (c = hbar = 1, V = m^2 phi^2/2 + lambda phi^4/4). Free waves obey omega^2 = k^2 + m^2. The strip under the map is the cross-section of phi along the dotted horizontal line (follows the pointer). Leapfrog integration, 96 x 96 lattice.