Yesterday I posted an article to the arXiv, “A Trisectrix from a Carpenter’s Square.”
Abstract: In 1928 Henry Scudder described how to use a carpenter’s square to trisect an angle. We use the ideas behind Scudder’s technique to define a trisectrix—a curve that can be used to trisect an angle. We also describe a compass that could be used to draw the curve.
I also made a GeoGebra applet to accompany the article. Give it a try.