Hello Saxium, and welcome to the Monastery!

The following quote from perlsub may throw a little more light on the answer given by roboticus:

A my has both a compile-time and a run-time effect. At compile time, the compiler takes notice of it. The principal usefulness of this is to quiet use strict 'vars', but it is also essential for generation of closures as detailed in perlref. Actual initialization is delayed until run time, though, so it gets executed at the appropriate time, such as each time through a loop, for example.

So the rationale behind the behaviour described by roboticus — The printme subroutine uses the ... [$x] in scope at the point where it's compiled. — is to facilitate closures as a feature of Perl. Here are some references on closures, in case you’re interested:

• Whats-a-closure of perlfaq7
• “Persistent variables with closures” in perlsub
• Section 4 of perlref#Making-References
• Closure on Closures by broquaint

Excellent question, by the way!

Hope that helps,