[Adam Y.]

There are square, elliptical, and I believe triangular gears as well as linear motion convertors.

The exhibit had a linear motion converter also but no triangular gears. They also had some type of gear set called scroll gears.

I see you are from Long Island so I don't know if you have been to the Museum of Science and Industry in Chicago. They have several unusual gear clusters on display in the stairwells. There are square, elliptical, and I believe triangular gears as well as linear motion convertors. If this is the exhibit to which you are referring, the gearsets shown are for demo and are not practical.

I have never been there but it sounds interesting. The museum exhibit Im talking about is in Boston. They also have an extremely large assortment of linkeages and engineering devices on display like the geneva mechanism. Im not sure how old the exhibit is but it does seem fairly worn. I can't even read some of the devices name. The only thing that fascinated me about this is that they really didn't give an explanation why the gears are rarely used and trying to count the changing revolutions of an gear is impossible by eye.