Ok, @sandwichmaker , here goes! <cracks knuckles>. I'll begin with the *multivariate* case, which is where I actually got interested, in the mid-nineties: https://t.co/AP1PyDbP6P (use https://t.co/tfxiQBUsUD if that link doesn't work, and your library will open the ACM DL) 1/17

— Rob Corless (@corless_rob) January 7, 2022

How medieval astronomers made trig tables https://t.co/aFgLnNZLh4

— Analysis Fact (@AnalysisFact) January 4, 2022

Here's a surprisingly unsolved problem in math:
Proof of the existence of the perfect Euler brick – a rectangular parallelepiped with integer-length edges, integer-length face diagonals, and an integer-length body diagonal. pic.twitter.com/iKpc8YdT49

— Fermat's Library (@fermatslibrary) January 4, 2022

Where do the circular ripples come from? What determines how fast they ripple? Video: https://t.co/LslsBOgU8m pic.twitter.com/LkG6eOyVW5

— Henry Segerman (@henryseg) January 1, 2022