|I recomend to you my comment at the top ofthe column of comments: I claim that it works: Straightforward in angles between 0 and 180, higher angles need to be partitioned into a straight angle ( tri is 60 easy) and an acute or obtuse angle the smaller ( or residual) angle is then trisected using my described technique asnd then the trisect copied to augment the angle of 60 derived from the straight angle, the composite angle being one third of the original angle