What's up with witch rings?
'Witch rings' are well-known novelty rings that show a size-change illusion when rotated. We have replicated the illusion of expansion of the reflections in the rings in a variety of contexts with animations, though not as yet so successfully imitated the sense that the whole ring expands and contracts.
Priscilla
P
Heard
David
D
Phillips
D006801:Humans; D007088:Illusions / Q000502:physiology*; D009039:Motion Perception / Q000502:physiology*; D012858:Size Perception / Q000502:physiology*