Minneapolis in 73: Not your ordinary Worldcon bid

In the distant past we made a t-shirt for Minneapolis in '73. Jerry Stearns made it, and the art is Ken Fletcher's. They were for sale at Midamericon I in Kansas City in 1976, at least, and probably at other times and places. There may have been several runs of them. It looked like this:

We recently found paper prints of the artwork, letting us make this nice scan: