This is an interesting and complex gear animation. It is complex not because it is hard to do, it is complex to find solution to a problem to design four gears fitting inside a fifth gear proposed in mathpuzzle.com. The problem was solved by Andreas Röver. I made this flash animation by imitating the gif animation shown in here. My animation is not as nice as the gif animation, because I did not want to spent whole my time to find correct arrangement of the gears.
My actual purpose was to use my Gear Draw program to create gears with different number of teeth's and radius. To do this I wanted to make this animation. I admire Andreas coming with solution to the problem, because it was hard for me even to imitate know solution.
Gears shown in this animation are drawn by using following parameters for each gear. Pressure Angle 14.5, Addendum 0.1 and dedentum 0.12. Pitch radius for 7 teeth is 0.5, 11 teeth 0.79, 13 teeth 0.93, 13 teeth 1.36 and 37 teeth is 2.64 respectively.