Eats Squid
It's got to do with Maths ..

If you add the combinations up .. it always comes to a certain set of numbers .. those certain set of numbers always have the same Symbol.

It's all Maths ..


It's my birthday!
Yea, youll notice that 15 is 1+5=6, 15-6 is 9, same thing with 16 or 17, 1+6=7, 16-7 is 9. All the other ones are worked out like that too so they have the same symbol as 9

YOull notice also that the symbol for 9 always changes which makes you think that it is not rigged.