I used one of those big machines (not this one) back in the day. But, for my money, the most beautiful calculator in history was the HP25 (https://en.wikipedia

I used one of those big machines (not this one) back in the day. But, for my money, the most beautiful calculator in history was the HP25 (https://en.wikipedia.org/wiki/HP-25 https://en.wikipedia.org/wiki/HP-25). Clear keys, spaced for errorless entry, and with that wonderful levering action that made it unnecessary to look up at the display to see if you entered the number correctly. The key colours, sublime. And the back, shaped to perfection. A pinnacle of design.