An ellipse rotating rigidly about its center may appear to rotate
rigidly or to deform nonrigidly so that it appears gelatinous. We use
this ambiguous stimulus to study how motion information is propagated
across space. We find that features that are quite far from the
ellipse's contour may have a strong influence on the ellipse's
percept, provided they move in a way consistent with the ellipse's
motion.  We show that the percept cannot be accounted for by
computational models that only pool constraints over a local area, nor
by models that propagate information along contours nor by models that
indiscriminately propagate information across space. However the
percept can be accounted for by a class of models that assume
smoothness in a layered representation.