If you have 2 copies of Embryonic, and time to kill, you can play tracks 16 (Silver Trembling Hands) and 17 (Virgo Self Esteem Broadcast) in sync. Start track 17 at 10.5 seconds after track 16. You can do this quite easily in GarageBand (other music software is also available) by dragging the mp3 files in and adjusting the start time with snap to grid turned off. Panning 75% left and right works well.

It's not earth-shattering but you do get a whole other layer to the song with some backing vocals and spooky voices/noises.

I wish I didn't notice things like this.