Each dot carries a spin, up or down, and wants to agree with its neighbours. Heat is noise: the chance to flip against the crowd. Warm half up, cool half down — the tapestry is the argument between order and heat.
Below T꜀ = 2.269 (Onsager's exact result, 1944) the lattice spontaneously magnetizes: domains grow, dots align, |m| climbs. Above it, thermal noise wins and the magnet melts to zero. Slide across the mark and watch the phase change happen under your hand.
Click any dot to pin its spin — a seed crystal for domains to grow from. QUENCH flash-freezes the system so domains race across the lattice like frost. SWEEP breathes temperature up and down while the curve of |m| versus T is plotted live.