Fig. 2.

Occlusion, paradoxical occlusion and containment. (A) Simple occlusions. (Top) An object (1) is in front of, and occludes a second object (2), or (bottom) is behind, being occluded by (2). (B) Dynamic containment occurs when a switch in boundary ownership (orange arrow) between (1) and (2) signals a dynamic ‘paradoxical occlusion’, where the boundary switches fromoccluding (2) to being occluded by (2). (C) Static containment at a low view is detected as a static 'paradoxical occlusion', where (1) occludes (2) and (2) occludes (1) along different parts of the common boundary between them. (D) Static containment at a high view: the common boundary is owned by (1), separating it from the ‘back’ region of (2). (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)