VI. Closure - a Gestalt principle of grouping that describes an innate perceptual tendency to close gaps or fill in missing parts to create wholes. In other words, it functions to complete shapes or images when parts of that shape or image are missing. For example:
 
Closure may function to
complete a shape which has been cropped
 
Close off a ground shape
 
Distinguish two overlapping shapes of the same color or value
 
It can also help to create a proximity grouping by completing a larger shape which contains several shapes within. For example the four small geometric shapes form one grouping because they are seen as being combined inside of the larger circular shape. (Also see "Combining Inside of a Larger Shape" under Proximity)