Design #3: Topological surfaces <a href="http://www.geom.umn.edu/zoo/toptype/torus/figure8/"> Figure-8 Immersion of Torus</a> <a href="http://www.geom.umn.edu/zoo/toptype/torus/ellipse/"> Elliptical Torus of Revolution</a> <a href="http://www.geom.umn.edu/zoo/toptype/klein/standard/"> Standard Model of Klein Bottle</a> <a href="http://www.geom.umn.edu/zoo/toptype/klein/figure8/"> Figure-8 Model of the Klein Bottle</a> <a href="http://www.geom.umn.edu/zoo/toptype/pplane/cap/"> The Crosscap</a> <a href="http://www.geom.umn.edu/zoo/toptype/pplane/roman/"> The Roman Surface</a> <a href="http://www.geom.umn.edu/zoo/toptype/pplane/boy/"> Boy's Surface</a> <a href="http://www.uib.no/People/nfytn/hunttxt.htm"> Hunt's Surface</a>