From: The World In Your Head by Steven Lehar

Fig. 4.5 (A) The perception of closure and figure/ground segregation are explained in the Gestalt bubble model exactly as perceived, in this case as a foreground square in front of a background surface that completes behind the square. (B) Even irregular and fragmented surfaces produce a figure/ground segregation. (C) The perceived boundary of the fragmented figure follows the global emergent gestalt rather than the exact path of individual edges. (D) Closure is also defined in three dimensions, as the tendency for objects to be perceived as enclosed in depth.