At the weekend I was looking at a safe with a 3 wheel S & G combination lock. The owner has forgotten the combination but has some 2 digit numbers which he knows comprise the combination. There are 6 of these.

I contacted my younger brother, who is something of a whiz at such things and asked him how many possible combinations there are if we assume that the combination is neither a rising nor a falling sequence. He calculated that there are 80 possible combinations. He then proceeded to write a bit of code which has crunched the numbers and given me a list of all 80 possibles. Isn't that neat?

So my next job is just to go back to the lock and flick through all 80 possibilities and hope that the owner is right.