The gym here has these "heavy-duty theft-resistant" locks they let you use to lock lockers (amazing concept, huh?). I was playing with one of them today. It's a basic combination lock—single dial that goes from 0 to 39, 3-number combination (X, Y, Z), and the following steps to open:
When step 5 is done the lock opens.
The first problem is that if you replace step 4 with
the lock still opens when step 5 is done. In my case Z and Y were "34" and "0" respectively, so it's not like they were close together....
The second problem is that the lock makes a nice loud click when Z is reached in step 4 (which admittedly makes the first problem rather academic).
I have to admit that these look more difficult to saw through than typical high-school locker locks, but from a pure codebreaking standpoint they are much easier to open (only about 400 possible combinations, since there is no need to guess Z; on a lock on which all three numbers need to be guessed there are more like 8000 combinations).
More and more of my students seem to think that sets can be "seperated". The Web strikes again. Bring on the claims that spelling is arbitrary anyway, that languages evolve, and that misspelling a word is OK if everyone does it. Then consider that this is not a word but a technical term in this case, and misspelling it means that you're no longer talking about the same thing. Goodbye, clarity of expression. Hello, "I'll spell it however I like; the reader can sort it out!"