this is an idea which i have seen attempted solutions for everywhere. i am doing my A-level physics coursework on it.  most theories seem to depend on magnets or unbalanced torque in both circles and triangles. obviously conventionally this is not possible,  however any ideas on the topic would be appreciated. i completely understand why in triangles and circles you cannot have unbalanced torque of you are rotating the object or something around it, but what if you had a triangle with an extended side so that a chain of balls of the same mass going around the triangle would be biased one side of the triangle as the 'weight would be uneven which is impossible in a normal triangle.  that way there would be biased torque but im not sure if this would work still, as im not sure if the extention on one side would set the masses at the underneath of the triangle in an imbalance that would counter the bias and therefore create equilibrium once again. please send information you may have. i am not really trying to solve the problem, just explain why many ideas dont work and look into the subject explaining methods which have been attempted.