What is a pinned square?

A pinned square is a term often used in mathematics, particularly in the context of combinatorics and graph theory. It refers to a specific arrangement of points or vertices in a square layout where certain points are fixed or "pinned" in place, restricting the movement of other points. This concept can be applied to various problems, such as those involving geometric configurations or optimization tasks. The pinned points serve as reference locations that influence the overall structure or relationships within the arrangement.