Nesting is where you put a block (loop or "a" block) inside of another.   It just will not continue the first block until it comes out of the second or nested block  This can be done with all loops and blocks: IF, FOR, DO, or SELECT.   Example:

Do While a

Do Until b  'the first do can't run the rest of its code until this loop ends.

Loop

Loop

By: Matthew Holder