Is there a significant branch of geometry that has been overlooked? Unlikely as it may seem, D-Form geometry provides designers, architects, sculptors and artists with a vast, new vocabulary of three-dimensional forms that are easy to play with and make. Easy as they are to fabricate, D-Forms are proving equally hard to predict with computing. This geometry exploits some interesting properties of developable surfaces that, among other things, will enable you to ‘square the circle’.