Generalized Trisection Construction
This Demonstration shows a generalization of Pascal's angle trisection. The red segments have the same length. Vary so that the last red segment overlaps the top ray of angle , which is then times the size of angle .
 J. Bryant and C. Sangwin, How Round Is Your Circle?: Where Engineering and Mathematics Meet, 1st ed., Princeton, NJ: Princeton University Press, 2008, pp. 106–107.