Table 2 summarizes this image sequence. We tried all possible combinations of two out four mirrors rotating. The basic sequence of shapes was the same for each combination, but there slightly different variations. One when the two rotating mirrors are facing the same direction, and another when they are on opposite sides facing each other. As an example, the spirograph image has short round lobes if the rotating mirrors are on opposite sides and long slender lobes when they're on the same side.
Similar differences occur for each image in series.
Image sequences for two mirrors The series of shapes appears regardless of the constant motor's rotation speed. Each series begins with the rotating ellipse. When the rotation rate increases by small amounts, the image rotates faster until it reaches the point where it suddenly becomes a 5-lobe spirograph or star. The same is true for each successive image in the series. Once an image appears, a very small change in motor speed will change the speed or direction of the image rotation.