However, in the key of C major, the same progression would go F-C-G-Am as the IV chord in the key of C major is F major, the I chord is C major, and so on. Step 9: So now that we have the diatonic ...

Using MIDI over USB, it plays the I-V-vi-IV progression in any key. It plays in chord mode, arpeggiated mode, or mixed mode at any sensible tempo. You can check out a video of the 4chord playing ...