Thirty-two Goldbach variations

We give thirty-two diverse proofs of a small mathematical gem — the fundamental Euler sum identity ζ(2, 1) = ζ(3) = 8 ζ(¯/2, 1). We also discuss various generalizations for multiple harmonic (Euler) sums and some of their many connections, thereby illustrating both the wide variety of techniques fruitfully used to study such sums and the attraction of their study.