This time the site goes deeper into the geometrical shapes in drawings. If you think of a castle, you can see the shapes.

This drawing was on the website, and here you can see the pyramids, cylinders, cones and prisms. To master the architectural part of drawing, its easy to just remember how to draw these geometrical shapes. This is because usually you can just combine the 3-D shapes to make a building like how this castle was built.

http://mathforum.org/workshops/sum98/participants/sanders/Geom3D.html