A copy of Fraser's spiral
The term "spiral illusion" had long referred to the spiral illusion of the Fraser illusion (Fraser, 1908) before we elucidated that any tilt illusion can form spiral illusion (Kitaoka, Pinna and Brelstaff, 2001). This page shows a copy of Fraser's spiral produced by PC programming. <2003/8/30>
Fraser, J. (1908) A new visual illusion of direction. British Journal of Psychology, 2, 307-320.
First presented by Fraser (1908); Reproduced by Akiyoshi Kitaoka (2003)