The Science Complex Lecture Hall (SC LH) at Trent University has a pulley hanging from the ceiling, apparently for occasional use in physics demonstrations. Over three years (1996-1999) of teaching Mathematics 110 - Calculus of one variable in SC LH, I developed the habit of periodically hoisting various objects using this pulley for the amusement of my class and those after mine. This reached a peak of sorts when I constructed an elaborate mobile over several weeks in the fall of 1998. Here is a picture of it at an early stage:
At least, I thought that was the peak, but several of my students (Jacob Bondre and Jared Warren, helped by Mark Waenink, Ken Hoard, and Ian Bratberg, and photographed by Robert Morralbee) did me one better. They procured a climbing harness and in the last lecture, on 8 April, 1999:
Jacob (striped shirt) and Jared (plaid shirt) are the ones pulling on the line, and Mark is the one trying to hold me up.
Mark is joined by Ken (green shirt) and Ian (white shirt). Success!
I brought along the yellow rope for lateral stability.
Thus it was that I briefed the class about the final exam from several feet in the air. They got a better average on the final exam than either of the two previous years. Hmmm...
The whole is on the left, a detail below.