This strongly reminds me of “Page’s Pages”, an odd little set of 4 or so similarly beautifully-handwritten (if incredibly densely-packed) double-sided pages at the front of a quadrille graph paper notebook I bought at the school store. It crammed equations, methods, and incredibly useful trivia for algebra, trig, geometry, calculus, physics, chemistry, and engineering in those 8 print pages.
I actually bought a few of them, with the intention of giving them to a few friends, but none of them were interested. Idiots; they were a LOT of help on open-note tests ^^’. I kept a couple of them for over 20 years, til they finally were lost in a move.
