Here's a triangle folding app in p5. Basically you can "Build" a triangle by clicking points, then click on "Fold" and then a vertex of the triangle to fold, when you let go of the mouse then the crease of the fold will appear on the triangle. The "Circle" button will create a circle with a chosen point as center. The way we used it in class was to randomly try circles and make them go through all vertices of a triangle, when we give up, then we draw perpendicular bisectors by folding the triangle, then use the circumcenter to draw our magical circle! The same can be done for Incenter.Â