Here's a Sisson Sector: http://www.royalobservatorygreenwich.org/devblog/wp-content/uploads/2014/03/Sissons-Equatorial-Sector.jpg http://upload.wikimedia.org/wikipedia/en/b/be/Duchamp_LargeGlass.jpg - Pynchon-l / http://www.waste.org/mail/?list=pynchon-l