BTW, you can always simplify (if <expression> nil t) to just (no <expression>).
Also, what's that i variable doing in valid?? I don't understand how valid? works..
You _really_ don't want to be making pass-by-reference changes like incrementing i inside some, since there's no guarantee about the order in which it'll run. If you want imperative updates, just use an explicit loop like each.
