[suranyami]

Not a course, as such, but reading “Measurement” by Paul Lockhart, of “A Mathematician’s Lament fame.

I’ve never read anything that so clearly communicates and leads you into a state of mind that COMPELS you to prove mathematical conjectures from first principles.

I found myself furiously sketching geometric proofs and simplifying algebraic conundrums with an enthusiasm I haven’t experienced in decades.

And a course on sewing for beginners and continuing Japanese.