In one of the figures, Listing's plane rotates temporally by as much as the eyes converge.
In the other Listing's plane stays fixed.
Can you guess which is which?
To check change your viewpoint to "in front" of the eyes.
Copyright © 1996 Tutis Vilis and Douglas Tweed University of Western Ontario London Ontario Canada Updated October 28, 2005
Comments welcome. Email to tutis.vilis@schulich.uwo.ca