The grape codes looked like they were in base 2. The only exception was that there could be digits higher than 0 and 1. Another thing I noticed is that when you shift it to the left it multiplies by 2 and when shifting to the right it divides by 2. This is the same for all bases except you divide or multiply by the base number. An example is when you shift a number in base 3 to the left. It multiplies by 3.