I didn't have the laser close enough to my acrylic and so it didn't cut all the way through and I ended up breaking it in half while trying to press the piece out of it.  Luckily there were some scraps of plywood that I thought were the right width, but were slightly larger than 1/8", so they don't fit together, but I did get to make sure that the leds were spaced properly, and it appears perfect!

I'm going to head to TAP plastic this weekend to get more acrylic, and the tube that this will all fit into, so that I can try again, with the laser at the right height.