Ulrich Schwanitz claims to have created a 3-D Penrose triangle without resorting to the usual optical illusions. We'll believe it when we see it.

PENROSE TRIANGLE The impossible triangle (also called the Penrose triangle or the tribar) was first created in 1934 by Oscar Reutersvärd. Roger Penrose attended a lecture by M. C. Escher in 1954 ...