In any case, he always mentioned that combinatorics was a matter of inclusion and exclusion (the Moebius function) and putting together and taking apart (as in puzzles, Hopf algebras). Now, I was working on various exact solutions to the two-dimensional Ising model, essentially a combinatorial problem. Unfortunately I never pinned him down long enough to be educated by him. He always focused on my son and my father role, and if we went out alone, his main concern was to let me be free of parental pressure for a few minutes.
Parts of a color Xerox machine (Phaser, originally Tektronix) was near the garbage. There was toner, and there was imaging elements. I took one of each, blue toner, yellow imaging elements. New they were $200+ and about $500, respectively (so maybe $2,000 for a complete change, three colors), according to the internet. In any case, the toner cartridge was not interesting, once you realized how it released toner. The imaging elements, and there was one for each color, probably were the place where the image was deposited and affect the conductivity of a roller, and on which toner was deposited on its way to the paper. (Much like offset lithography, there is no direct contact but there are transfer rollers.) I just took it apart, and what was wonderful was that it was all held together by plastic pieces clicking into each other, with just two screws holding on a metal part. In other words, it just clicked together for 90% of its putting together, and you just had to hold back the clicked linkage and pieces came apart immediately. Almost all plastic, except for the roller surfaces. Quite nice. (You have to regularly vacuum up the toner that comes out.)
So you have perhaps ten parts, most of which are molded plastic, except for the rollers, and the small circuit board. And they just fit together, click!
By the way, cell phones and many toys have distinctive screws, and you need the right tools to take them apart. They never just click together, either. Still I find myself taking whatever it is apart. I have no plans to put them together again. Sometimes one finds a part, say the small lens of a cellphone camera, that is very very nice to have.
I always say that I did not continue to do experimental physics because I did not like working with equipment, and I did not like big experimental groups. I am not sure, any longer, about the equipment. It's not that I am good with it, but I do like to play and figure out what is going on. Probably small nuclear or solid state physics would have been better for me. Who knows, after 45 years?
I just made a photobook of my son's drawings. I tried to put it together myself, but Shockwave did not work, and I let it put things together as it will, and then made minor changes. What's interesting is that it does a decent job.
Shutterfly photo books offer a variety of layouts and cover options to choose from.