Hey, I'm back. Today, we have not a knowledge wheel, but a calculator. We've had these before.
I can't pretend to know anything about how to use this dang thing. So, I'll just give you the specs: This wheel is 7.5 inches across and is .25 inches thick. Plus it's a bit heavy, being made of some thick plexiglass.
As you an see, there are a couple of moving parts that pivot away from the surface. One is a circle that is the same size as the wheel and the other is an arm of sorts that rotates around the other side. These are used for calculating! You can tighten the little screws. Alas, there is no date on this.
No doubt there are more sophisticated ways of doing what this wheel does, but there are none cooler.