This is a case for Adafruit's Circuit Playground or Circuit Playground Express board, (https://www.adafruit.com/product/3000) which will enable you to place 3mm light pipe or fiber optics in line with the onboard LEDs. It includes buttons so that you can access the Circuit Playground's onboard control buttons without opening the case.
It's got tabs for sewing onto your cosplay project and a hole in the back for any other wires or devices you want to run from the Circuit Playground.
Remember to come back and post what you've printed as Make.
It's good for the designer and the community (that means you)!
To post a Make, come back to this Thing and click Post a Make.
Or, you can use the Thingiverse Mobile app found on
and the Apple App Store.