Optical Perceptions

Kaleidoscope Stars

The middle star rotates — but does it move smoothly? Physically, the rotation is perfectly even, as you can confirm by adjusting the slider to make parts of the arrangement more transparent. Yet the motion can appear to jolt or hesitate, especially when the contrasts between the rotating and stationary stars change. Depending on viewing conditions, some people even perceive a brief backward jerk of the rotating star when everything visually aligns — a striking example of how our eyes and brain can misread perfectly smooth motion.