The following sessions were fun, I was looking at a swinging ball through a prism trying to see in double or wearing Polaroid or green-red glasses looking at two transparencies (Vectograms) and trying to see them together.
For homework, I had to hold a prism to one eye and look at objects and try to see them in double, forcing the eye with the prism in front of it and the other eye to both be viewing simultaneously. I waved my finger around my face, seeing it in single, in duplicate, single, duplicate, and so on. I could not keep the double finger for a long time.
I also had to wear Polaroid glasses and look at myself in the mirror, walking backwards until I could no longer see both of my eyes at the same time. For a moment, I could see both eyes and then one lens would go black, showing that my brain was no longer processing the vision from that eye.