Breathing Square

These animations were created by rotating a black square over four white circles, or a blue square behind four holes in a black surface. Surprisingly, both squares appear to "breath", they contract and expand as they rotate (Meyer & Dougherty, 1992; Shiffrar & Pavel,1992). This is strong evidence that motion integration does not use a rigidity constraint (Ullman, 1979). In principle, assuming rigidity to integrate successive frames one could recover the rotating square. However, the local perpendicular components at the square sides prevail here, generating the deformation.


created by Fauzia Mosca and Nicola Bruno