My Gal is taking a high end math class. She came home one day and pointed out that in math a circle that begins a line denotes a line with no origin and tied that to classic sigil creation. Note the classical style sigil in the picture. It is drawn with the beginning marked with a 'no origin' symbol.
You cabalists out there may recognize a link between this and three veils of negative existence Ain (No Thing), Ain Soph (Limitlessness), Ain Soph Aur (Limitless Light).
Can the style of these sigils be taken to imply or mean that the magick emanates from the absolute source? I don't know what our predecessors meant by using this form. However, I will know what I mean the next time I draw one.
(sigil from: http://astroqab.com/jacobwheel/images/designs/vahoiel_sigil_line.gif)
(tree of life with veils: http://email@example.com/Treeoflife.gif)