Source: Image of Curvilinear Shape, by Maria Tucker
A shape is a two-dimensional plane with a clear, identifiable boundary.
Two-Dimensional is defined by something with two coordinates: width and height.
Plane is an area within a two-dimensional surface that extends to a specific direction or position. A plane is a particular kind of shape.
Shape Variation relates to the diverse range of contours that can be implemented on the boundary of a shape such as angular, curvy, straight.
A shape that is characterized by straight lines.
A shape that is characterized by curvy lines for boundaries.