Basic Shapes, ContinuedCones appear triangular in shape but, have a circle or ellipse as a base. Lines converging to some point above or below the base determines theheight of a cone. Shading defines the roundness of cones. Figure 3-16 shows a basic cone. Figure 3-16.A cone. Figure 3-17 shows how shading changes the cone into a tree. Figure 3-17.Changing the conical form to trees.