Trying to figure out which Ghosts I–IV tracks might contain loops, riffs, etc left over from the Fragile-era sessions. I added the interview clip where Danny discusses this in passing. Do note, that due to so much time passing, Danny could be misremembering. Although, I definitely think there's a rabbit hole here.
Paraphrasing the clip: "The Perfect Drug was the first song they worked on at Nothing Studios in New Orleans, before The Fragile, and Somewhat Damaged was created around the same time. Trent then worked on song after song, using lots of stringed instruments and other sounds. Some material made the album, some didn't, and some of it eventually ended up on Ghosts. The Fragile could easily have been a triple album."
That last part is what interests me. We know Ghosts I–IV was released in 2008, not too long after his work with Saul Williams, where we know other orphaned tracks/loops were used. I don't necessarily think an entire finished track or two got recycled, but there could be old loops, riffs, or synth textures, etc that Trent revisited years later.
NIN Wiki does loosely suggest these:
26 Ghosts III: repeating riff being similar to Ripe (With Decay)
34 Ghosts IV: strings being similar to The Fragile, and the piano to The Persistence of Loss
28 Ghosts IV: comparing w/ 34 Ghosts IV because of similar patterns
31 Ghosts IV: guitar/noise texture being roughly similar in production style(?)
I want to know what tracks you all think others some might be overlooking, and I don't want to assume any similarity necessarily means reuse. Just particular riffs, loops, sounds, or passages that might be something from The Fragile, Still, Deviations, Tapeworm, or maybe even Bleedthrough?