flint axle
7 9 13
this is a saying that might be local to denmark where i live, but possibly in other countries as well. In denmark when you mention something bad not happening, people sometimes follow it up by saying 7 9 13, and knocking on the table. To dissuade the bad luck from actually happening.
Why it's a thing, i do not know. But i think it's a concept that'd be very easy to apply to a joker, giving chips or mult to 7s 9s and Kings