It did not look unusual in any way - generic road/mountain bike, full frame, etc. except for the odd rims. I’ve seen aero rims like those in TD’s examples - sometimes almost full-wheel shrouds - but these were different. They seemed to be completely ordinary spoked wheels, normal inside diameter, but instead of a quarter to half inch of rim and inch or two of tire, it was the other way around.
I thought from a distance that the tires had whitewalls - I remember those from old-fart bikes when I was a kid - but nope, shiny metal.