Note: You can rotate the spins in a chosen block as follows. First click step or stop to stop the simulation, then click your mouse to select a block of spins. Now click your mouse again and hold it down to change the orientation of the selected spins by moving the mouse around the center of the chosen rectangle. Lastly, click continue to continue the simulation. I forgot to point this out when I posted this applet years ago.

Source Code:,, and
Note: Applet may not work properly with Netscape, try the latest version of Internet Explorer.