Designing is a task which requires a combination of technical knowledge, skill, training, patience and artistic imagination. Most of the designs made by man or available in nature have inherent symmetry in them. Considerable mathematical analysis is required to discover an order in such designs and encode them in mathematical descriptions. Moreover, such analysis is usually specific to a particular design (or a class of designs) and is difficult to generalize. Geometric modelling can be used as a design tool to avoid unnecessarily tedious or repetitive tasks. This allows the artist...