I saw him featured on a show about money and counterfeiting. And the question he raised was really really interesting to me. If he made a drawing of a cat or a dog and offered to trade that for a meal it would be simple barter, but because it looked so similar to currency it freaked out the authorities.

And that makes you ask "what is money really?" and "what is value?" His drawings of currency were always "worth" more than their face value to collectors. And as far as I have heard he never tried to "trick" someone into believing it was actual currency. It was just a really detailed drawing.

Now I think I'll never get a chance to own one of his bills.