name that ex song by completely non-standard music notation

saw them play last night. seen them twice in the last few years, but never been bothered to pick up anything by them post 1988/89. last night for the first encore, though, they played a really great song that i assume is recent. asked the merch gal, she said it was from Turn (2004) but was too busy to tell me which song it was, and she may have actually been thinking of "prism song" which was their second encore.

so. last night they were a quartet -- just the two guitars drums and vox. the song in question had one guitar playing a rhythm that alternating back and forth between a high "chord" and a low "chord" (they were not traditional chords and more like the way david fair describes how to play guitar). the pattern was:

1 2 3 4 1 2 3 4
||:l h l h l h |h h l h l h:||

the other guitar followed on a higher pitch and then switched to melodies that weaved around this, also based on just 8th note progressions. and then of course, as they are the ex, it builds and builds and was quite an amazing song. couldn't catch any of the lyrics (which i know would make this much easier) because of the ol' bullhorn approach.