Size and position are incongruous: measurements on the Müller-Lyer figure.
D005403:Fixation, Ocular; D006801:Humans; D007088:Illusions / Q000502:physiology; D009903:Optical Illusions / Q000502:physiology; D012858:Size Perception / Q000502:physiology; D013028:Space Perception / Q000502:physiology; D014794:Visual Fields