This is what I used to mount the Neo Pixel Rings inside the star...

The two rings fit back-to-back with a Trinket in the middle (here's a refresher on how to wire-up your NeoPixel Rings).

USB port pointing up for easy access...

The LED rings will get a little warm... we need to let the star 'breathe' a bit. Either drill or melt vent holes in the top and bottom of the star.

Pass your power leads through one of your vent holes on the bottom and terminate with your female DC power adapter.

What about the code?

Really... the rainbow animation in the Neo Pixel strandtest example is beautiful. If you prefer something else, those examples provide a great base to work with.