|   | 1 |  initial version  | 
you should not give one set for every vertex, but one list for every vertex, using the local orientation around the vertex and cutting somewhere
 Copyright Sage, 2010. Some rights reserved under creative commons license. Content on this site is licensed under a Creative Commons Attribution Share Alike 3.0 license.
 
                
                Copyright Sage, 2010. Some rights reserved under creative commons license. Content on this site is licensed under a Creative Commons Attribution Share Alike 3.0 license.