In re de Castelet, 562 F.2d 1236, 195 U.S.P.Q. (BNA) 439 (C.C.P.A. 1977) (full-text).
C.C.P.A. Proceedings Edit
Process claims were denied for a method of generating curves, employing a computer in conjunction with drafting and milling machines. The claims recited a process for solving a set of mathematical equations, the solution being a set of points along a curve, rather than a process which merely used equation solutions as one step in achieving some result other than the solution of the equations. The claims were rejected as drawn to nonstatutory subject matter, since a patent containing the claims would in effect be no more than a patent on the equations themselves.