Lauren- Law of Similarity

The law of similarity is a Gestalt principle of organization holding that parts of a stimulus field that are similar to each other tend to be perceived as belonging together as a unit. This is in an assumption that all other aspects related to the stimuli are equal. We tend to group things together based on their similar aspects.  For example, in the picture below, many people see vertical columns of triangles and circles because they group the similar shapes together. Another example of this would be grouping laundry together based upon color.  

http://www.theinspiredeye.net/how-to-use-the-law-of-similarity-in-photography/

https://www.crafthubs.com/sorting-laundry/21262