I don't know the original source; suffice it to say that I saw it on a photo-copied piece of paper.
I have updated it to fit current North-American political and taxation trends...
Combined Canada / U.S Income Tax Calculation and Remittance Form
(Simplified) Form #1990-1a
North-American Free Trade Agreement Tax Treaty Tax Year 1990 How much money did you make? $_______.___ Send it in! $_______.___