The animated GIF files below were created with Mathematica, then tweaked with Microsoft GIF Animator. The Mathematica code used to generate these pictures is in the BeetleTracks.nb notebook.
These images show the changing paths of the beetles as they spiral in to the "counter-clockwise beetle center" of the triangle, as the shape of the triangle changes. (That is, the beetles are chasing one another counter-clockwise around the triangle.)
varying height | varying location of peak | varying side length | varying angle |