Fork and X

[Nefarias]

Nice and simple: Does Fork copy the value of X on the spell it copied?

I'm guessing it does, as the value of X is defined when it's being copied (as opposed to an X spell imprinted, for example), but I'm just making  sure. The only thing that makes me question it is stuff like Mind's Desire and Dream Halls, which in the reminder text specifically states that X=0, though they deal with a slightly different area.

[Jacob Orlove]

Fork copies a spell on the stack, and when a spell is on the stack X is whatever value the caster paid.

Mind's Desire and the like allow you to play a spell without paying its casting cost--whenever you do that, X is 0.