Reminds me of another Pulp Fiction quote:

"Check out the big brains on Mike"

We tried a couple different numbers @ the same time to verify that what ever the combination there was only one possible symbol but I only took Math 157 and couldn't do the XY crap to save my life.

 

Wasn't that moments before they shot him dead? Hmm....

 

So much for me giving the answer. It took me two times to figure it out and a third to check my conclusion, but I guess I had it right. I couldn't have described the answer as well as Mike did (excellent job by the way) that's for sure.