Masterclass in the Diatonic Circle, part 1. This portion featuring Tod Dickow on sax.
Solo piano style version of Freddie Freeloader, for beginners. With rudimentary bass line and right-hand chords, with melody on top. This uses the very utilitarian chord shape: tritone-perfect 4th. That is, an interval of a tritone (lowered fifth, or raised 4th) on the bottom, and a perfect 4th on top of that.