these wheels would have a hole in the middle significantly larger than their axes. they would be made of magnets formed so that the polarity of the outer edge opposed the inner edge. the axes would be of similar design, with polarity on the outside being the same as the inside of the wheels, and opposite their centers. a similar design would be given to the vertically-oriented spinner-parts. the result is a wheel which will not get junk caught in it because there is a sizeable space betwen the wheel and the axle, improved shock absorbsion (a great boon for those large or poorly-balanced loads), and much easier maneuvering. the one downside is almost no retarding force cause major damage with a heavily laden cart if you don't hang onto it, and parking on even the slightest grade is impossible.