I don't know how to explain it.

You just know this is going to end well.

So I've been intrigued by this old David Byrne song (from about 1997). It's called "Amnesia", and it's off his "Feelings" album. If you don't know the song, get it, it's good. I'll probably put up a midi in a few days, as I'll be moving house tomorrow and won't have the net until next week sometime.

Now, the chords are as follows:

(Verse/main theme)
| F# | D | F# | D |
| F# | D | F# | % |

(Bridge)
| Bb | D | Ebm | % |
| B | % | C# | D |

and it just alternates between the two, kind of like A-A-B-A.

Now it occurred to me just today that it could be explained with the use of a three tonic system (three keys, each two tones apart). This gives you the three keys F#, D, and Bb. We can now label the chords like so:

(I/F# = I of F#)

(Verse/main theme)
| I/F# | I/D | I/F# | I/D |
| I/F# | I/D | I/F# | % |

(Bridge)
| I/Bb | I/D | vi/F# | % |
| IV/F# | % | V/F# | I/D |

Would this be the best way to explain such a progression? It would probably make more sense if you had the melody to go along with it, but I can't really help out there until I can put the midi together.

I had another idea as to how to explain it:

(Verse/main theme)
| I/F# | bVI/F#m | I/F# | bVI/F#m |
| I/F# | bVI/F#m | I/F# | % |

(Bridge)
| ? | bVI/F#m | vi/F# | % |
| IV/F# | % | V/F# | bVI/F#m |

This way it seems a little simpler (F# with chords borrowed from the parallel minor), but it doesn't explain the Bb at the start of the bridge.

Questions? Comments? Suggestions? It's driving me batty, and not in the Jamaican sense.