Waaay back in 1984, my dorm room at the University of Waterloo (Ontario, Canada) had some double images on graph paper pinned to the bulletin board. I had a little Sharp calculator/computer and I had written a BASIC program to convert 3D coordinates to 2D coordinates assuming the points of view of two eyes in space. I created stereo images by painstakingly inventing objects with 3D coordinates and then plotting them on the graph paper in stereo and later connecting the dots.

I was able to see the stereo images unaided (eyes in parallel gaze, but focus nearby) so I saw depth! Being an enthusiastic first-year student at the Math faculty, I found it exciting to be able to create completely virtual 3D forms, even if it did involve incredibly slow plotting by hand.

Every calculus class where we were expected to sketch 3D shapes (for figuring out how to integrate them to find volume, or whatever) was a fun challenge for me, and I loved drawing the X-Y-Z axes and lightly plotting critical points and then sketching and shading in the rest.

Eventually, since I was studying Combinatorics & Optimization, I encountered Graph Theory and that really caught my attention. Here was a branch of mathematics which was focused on dots-and-lines (and basically nothing else!), with no real use for spatial representations except to avoid getting confused about the dots-and-lines (sometimes, on a good day, arrows). My sensibilities were bothered by this, but fascinated as well. How could it possibly not matter?!