NOTE: You can download the individual movies from here.
In the foregoing task it is perhaps quite easy to hit on the solution, but finding a justification (or proof) is quite challenging.

Finding a solution in the above task is perhaps equally easy, but finding a proof is harder. A nice challenge is to prove that the area of the triangle is proportional to its perimeter.

If you have any methods or comments about the original task, please email MT, post a comment on the MT/ATM website or send an email to