Explanation: For every triangle, three points are randomly chosen. The pen then starts at another random point. To draw each dot, the pen randomly picks one of the three triangle points, walks halfway toward it, and draws a dot at its location. Then it picks another triangle point, walks halfway to it, and the process repeats. If the pen randomly starts on the triangle, it will always be on the triangle. If not, all points will converge to, but not be on, the triangle.
