The monster: https://youtu.be/mH0oCDa74tE
Ideal packing of squares (some are elegant, 17 is not) https://kingbird.myphotos.cc/packing/squares_in_squares.html
The 4 color theorem was solved by reducing it down to 633 cases and just using a computer to find a coloring for each case: https://en.m.wikipedia.org/wiki/Four_color_theorem