The RectangleShape class represents a rectangle that you can place on the shape layer of a form or a composite field. OpenROAD displays any fields on the shape layer behind any fields on the field layer.

Usually, you do not need to associate a variable with a RectangleShape. However, if you want to change some attributes of the shape at runtime using the field function, you can provide a variable for the field. If a RectangleShape object does have a variable associated with it, the data has no meaning.