Hard To Build A Die (Prototype)

This is a simple prototype at the moment of a game where you play as a cube who wants to be a die. You roll onto die faces to collect them and win the level when all six faces are attached. The rules are as follows: A valid die has opposite faces sum to 7 (1 + 6, 2 + 5, 3 + 4) and you may not collect a face if it plus its opposite dont sum to 7. If a face on the die would sum to 7 with a new face, it must be the opposite face. So if you try to roll onto a face and these rules arent satisfied, yo...