Apparent changes in direction-of-rotation of a Necker cube (NC) signify perceptual reversals (PRs) equivalent to perspective reversals experienced when viewing a static NC. Rotations of 20 turns min-1 generate the same number of PRs as the static NC (Gorea and Agonie, 1997 Vision Research 37 2195 - 2206). We wanted to know if the pattern of reversals during an observation interval would also be the same. For the static form the rate of PRs increases during a fast phase and then becomes constant after 2 - 3 min during a slow phase (Borsellino et al, 1972 Kybernetik 10 139 - 144)
