Draw angle bisector with compass and straightedge.
[url]http://en.wikipedia.org/wiki/Bisection[/url]
[url]http://en.wikipedia.org/wiki/File:Bisection_construction.gif[/url]
Repeat,
[url]http://en.wikipedia.org/wiki/Bisection[/url]
[url]http://en.wikipedia.org/wiki/File:Bisection_construction.gif[/url]