Understanding variable binding visibility

Can someone explain to me what this means, with an example?

"For any use of these variable-binding elements, there is a region of the
stylesheet tree within which the binding is visible; within this region, any
binding of the variable that was visible on the variable-binding element
itself is hidden. Thus, only the innermost binding of a variable is
visible."

For some reason I just cannot grok the meaning of this, nor can I reconcile
it with my understanding of shadowing. "Innermost binding" to me implies
that a variable can be bound more than once. But that would seem to conflict
with what the section on shadowing says.


 XSL-List info and archive:  http://www.mulberrytech.com/xsl/xsl-list