This video supplements Figure 2 in the publication:
The movie demonstrates the depth ambiguity of the silhouette in the centre which can be interpreted in two ways. The two interpretations differ in the perceived order of the surfaces of the body in depth as can be seen in the figure below. The left column illustrates the interpretation in which we look at the figure's back in the first frame (top). As a consequence, the figure rotates clockwise as we go though the sequence of frames (from top to bottom), and we look at it from a slightly elevated viewpoint (10 deg). In the right column we illustrate the other interpretation. We look at the front of the figure in the first frame, the figure rotates counter-clockwise, and the viewpoint is 10 deg from below.