The applet below is a simplification of the Light Mill applet, in which a single plate (hotter on the black side than the white side) is constrained to move only horizontally in a container with wrap-around topology: when anything reaches the left or right edge it moves instantly to the opposite edge. (The top and bottom edges are ordinary walls.) All the physics for this applet is essentially the same as for the Light Mill applet; this version basically just changes the geometry to make the situation less complex. Note that the width and height of the container are 1.0, the same as the radius for the Light Mill applet, so the area of this container is smaller.
Some results obtained from this applet are plotted on this companion page.