The Principle of Proximity

Objects that are close together in space or in time tend to be perceived as belonging together, as forming a single group. For example, when identical dots are arranged in a grid where the horizontal gaps between dots are noticeably smaller than the vertical gaps, the resulting display does not look like a single square pattern of unrelated dots; instead, it is perceived as a series of separate columns of dots (or, arranged the other way around, as separate rows of dots) -- with the dots t …