Portal is probably one of the only games I could play over and over again. You always get something a little different. This, however, is incredibly different. It’s the Portal you know, except it’s on a scientific calculator.
This 1942 ad for a comptometer is just perfect because first of all, I had no idea what a comptometer was (a mechanical calculator, basically) and second, the spec sheet is wonderful: no glare dials, elimination of non-essential zeroes, and a “Keystroke Censor.”