DEJA VU!

From studying this thread at http://www.subdivisionmodeling.com/forums/showthread.php?t=8000 I have been able to get more of an undestanding of the more complicated mathematical side if topology. Looking at "E" and "N" poles. An "E" pole has 5 edges connected to it and an "N" pole has 3. These are the ideal poles when making making a curve in the shape or an extrusion such as the eyes or the ears and you need to make a break in the basic grid layout. This makes perfect sense when looking back at my A level maths. In an algorithms module, we studied what is called eularian (I think thats how you spell it) maps. These are maps that you can map out in one line without going over an edge twice, for an ideal route. To cut through all the mathematical jargon, we worked out that to form a eularian map, axes had to have either 3 or 5 edges connected. JUST like 3D topological extrusion rigging. So the ideal mapping of a topological layout when deforming to create and ear or pit for an eye, is in fact a 3D eularian map.