A fun brain teaser

The following sentence is a classic one for the proper place of punctuation.  Imagine if you were taking dictation and someone says:
"That that is is that that is not is not but that that is not is not that that is nor is that that is that that is not."
What is the correct punctuation?
(Actually, if you phrase it correctly from dictation in shorthand, you would be able to come up with the punctuation!)

(by chuck for everyone)