Very cool! I'm impressed. One of these days I'll have to try to learn how to rig lights like this.
It's way easier than it looks. They key to it, and one I find not a lot of people do, is using a resistance calculator to solder in the correct resistor in-line so that the lights run on the correct voltage.
On this TIE, most of the lights can run on 3.0-3.2v. By using the right resistor, I can run the whole thing on 2x 9v batteries in parallel setup, and the lights won't be under or over run, and the packs last forever. Some people will just hook up lights that are sorta close, but the lights can either be too dim, or too bright and will burn out sooner.