This tutorial references measure 55 to 93.
The composer settles into A minor through these measures and reinforces the A minor tonic to Neapolitan progression. (A minor to Bb Major chord) He elaborates, varies, and introduces a beautiful contrapuntal interplay of voices between treble and bass in measures 69-87. (All in A minor)
With a touch of majesty, Beethoven sneaks in a G7 chord that terminates the chromatic (half-step) movement in measure 69, leading to C Major, though not for long. A minor is promptly reinstated with a lovely dialog transpiring between treble and bass. (In counterpoint)
Not soon enough, the composer meanders back to the opening ROLLED chord which is the Dominant of D minor, the home key –and we are at the beginning again, with a REPEAT.
Part ONE: Beethoven Tempest Sonata in D minor
Part TWO Instruction
Part THREE Instruction