User is getting a worksheet with lots of columns.

They want a button atop each column that acts as a toggle - like the column
headers in Windows' directory windows do: Click on it the first time and the
whole sheet gets sorted by that col's values ascending. Click on it the second
time and the whole sheet gets sorted by that col's values descending.

If somebody could point me to an example it would save the client a few of my
man hours and maybe give me some "best practice" code instead of what I'd cobble
together from scratch.
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PeteCresswell