Thomsen's Figure

Thomsen's figure is illustrated by the following process. For any triangle , pick a point on opposite . From , draw a line segment parallel to intersecting at point , then from there a segment parallel to intersecting at . Continue through the figure. Thomsen's theorem states that the final segment from parallel to terminates at the original point .

Drag the triangle vertices , and to illustrate the diagram for different triangles. The slider moves between the vertices and .