"Transition functions between charts of an integer grid map always contain a translation by an integral offset.",
"Filling a non-regular hole of valence <i>n</i> in a cubic manifold B-spline with <i>n</i> bicubic Bezier patches with <i>G<sup>1</sup></i> continuity is impossible in general if <i>n</i> is even.",
"A closed, regular quad mesh is a topological torus."
