Try out revisions and multiple designs. I decided to give this as a gift to a friend who loves Fight Club. Not wanting to force him to be committed...
Step 3: LED layout
Layout a grid of 12 LED's equally spaced apart. This is where that ruler and basic math comes in handy.
The drill holes in for the LEDs to fit through.
Place LEDs through holes.
Secure with Hot Glue
Use more hot glue on top of the LEDs to diffuse the light.