The fact that we get to decide from numbers 10 to 99; actually, there are only 9 possible numbers to be place on our mind. So while there are lots of symbols provided, only U has to be anxious about 9 of them: 9 18 27 36 45 54 63 72 81
And the symbols are randomized; there is a peculiar consistency in the "crystal ball" : multiples of 9 always share the same symbol. Refresh the page and you'll see a new symbol, but 9 and 45 and 81 (and the rest of them) will always share that new symbol.
Every outcome of the math results in a multiple of 9. Every multiple of 9 always shares the same symbol, so it is inevitable that U and the Flash "crystal ball" will always select the same symbol...you're both doing the same math.
