The configure menu has been used to increase the size of the array. The temperature is still lower, well below Tc, and the display is set to run a single sweep cycle at a time. (In one cycle of the Monte-Carlo, every spin has had, on average, one opportunity to "decide" whether or not to flip.) In the first few steps, spins very quickly arrange themselves parallel to their neighbors giving local clusters of up and down spins. As the simulation progresses you see the large clusters growing at the expense of the smaller until the full magnetization has developed. (As the process slows down increase number of sweeps to compensate for the slowing down of the annealing process.)