Reading this whole thread reminded me of an old memory:
I must've been 14-15 when I found a combination bike lock on the street. Of course it was locked, with all 3 keys set to zero, and no sign of the combination that would open it.
I think the topic of permutations had already come up the year before in my math classes, so I was aware of the difficulty in figuring out the right combination.
The lock stayed on my dresser for 10 days. Then one afternoon when I was lying down for half an hour, I picked it up and casually started fiddling with the keys.
Click, click, click... nope won't open. I kept on clicking and failing for at least 15-20 mins.
Then suddenly I thought I heard something: One of the clicks had sounded slightly different than the rest.
I left the 2 keys where ever they happened to be and started advancing the 3rd one, one by one, click by click... And when I reached 7 or 8 (out of a possible 10) I heard a "clack". Pulled the 2 ends of the lock apart and voila! It opened. [img style="CURSOR: pointer" onclick=url(this.src); src="vny!://www.cheesebuerger.de/images/smilie/froehlich/a040.gif" border=0]