I threw together a "Shitty Add-On" (SAO) for the OnlyFeet Crew to pass around at DEF CON 31. This is the first time I tried offsetting the LED on the back from where it is supposed to shine through the front. It did not work quite as well as I wanted it to. Given the time and budget constraints of this project, I was not able to come up with a better solution.

Here it is plugged into the SAO port on another badge - you can see the red LED coming through the toes.