The spectacular optical illusion of the hollow mask is considerably improved by filling the mask with a transparent medium. The mask seems to stare more directly at the onlooker and its deceptive motions follow his movements over a wider field. The history of the illusion of the hollow mask is outlined and the legend of the Bust of the Tyrant is invented. Other ways of making a bust which follows the moving onlooker face to face are discussed.
© 1984 Optical Society of America
Original Manuscript: August 23, 1983
Published: January 15, 1984
Wolfgang Dultz, "The Bust of the Tyrant: an optical illusion," Appl. Opt. 23, 200-203 (1984)