The notion of line or straight line was introduced by ancient mathematicians to represent straight objects (i.e., having no curvature) with negligible width and depth. Lines are an idealization of such objects.,
A shape is the form of an object or its external boundary, outline, or external surface, as opposed to other properties such as color, texture, or material composition.
Visual perception of light wavelengths
Space is the boundless three-dimensional extent in which objects and events have relative position and direction