I have a soft spot for great orthographic drawings. I don't know why, but they are fun to look at and fun to make!
Orthographic projections are a way of describing what an object looks like from several different views. Orthographics are also called engineering drawings or plan views. Using a set of orthographics an Illustrator can easily draw the three-dimensional object from any angle and in perspective, isometric or any number of other drawing systems. 3D modelers often use orthographics to accurately create an object in a 3D application.
Heh.. found this too!