Not to be a Johnny Raincloud, but there are only a few ways to design a banner. The Aztecs and Egyptians both built pyramids, but that doesn't mean there was any contact between them. They both came up with the idea on their own. Me thinks this is most likely what happened here.
At press time, Harbaugh had sent Michigan’s athletic department an envelope containing a heavily annotated seating chart, a list of the 63,000 seat views he had found unsatisfactory, and a glowing 70-page report on section 25, row 12, seat 9, which he claimed is “exactly what the great sport of football is all about.”