Amodal completion

In Corrugation the vertical lines amodally continue behind elements in relief. In Long horse the perceptual tendency to unify collinear lines generates an effect that violates both the global context and past experience with proportions of normal horses.  In Checkerboard the apt positioning of colored disks produces unexpected crosses, due to the prevalence of local continuation of contours over the global context. Images with Circle sectors and occluding forms illustrate how the same sectors can be amodally completed in different ways, giving rise to four disks (behind the rectangles) or a central square (behind the cross). In the two tilings of Triangles and squares amodal completion generates a black grating (behind diamonds) or an oblique checkerboard (behind squares), respectively.