This was a commissioned item based on a build published by Kevin Rye, geek extraordinare at kevinrye.net. The STL files for the 3-D printed components and the code for the Arduino CPU are available at www.thingiverse.com/thing:2517312/, although there is no support offered if you have any difficulties interpreting the designs. I managed to adjust nicely to my first Arduino project, I thought.
The function of the cube, once activated, changes colors when it is moved or turned on a different side, just as it apparently does in the game. This will become a holiday gift to a true Portal fan, and I’m happy to help make it happen.