Hi John, There are a number of free graphing programs now that can do spirals and much more just from the equations. Some of them output .dxf files too. A couple that I remember off hand are "GraphCalc" at www.graphcalc.com and "Grapher" at http://home.attbi.com/~c1284j There are quite a few more if you want to search around the Internet.
Hope this helps! Edley McKnight Ancient in Oregon -
