One Note Samba

The joke of the tune is a melody on one note while the harmony walks down underneath. For a singer that's easy. For an improviser it's the opposite: eighty-two chords and nine tonal centres passing beneath you.

The chromatic descent at the start is the trap. Each chord in that sequence asks for a different reading, and thirty-six of the eighty-two are dominants — the family that allows the most choice and punishes the lazy choice hardest.