👉 A circumferentor is a figure in Euclidean geometry that has all its vertices at points that lie on a circle, and all of its edges are chords of that circle. It is named after the Greek mathematician Apollonius of Perga who studied this concept extensively. In a plane figure, if each vertex is located at a point on the circumference of a circle (the "circumference" of the circle), then the figure is called an "apollonian".
