Looks like fun but wonder how practical it would be for everyday living. Perhaps to only navigate around a quilt show, museum, mall or any other smooth surface, flat surface. I can't see them used while pushing a shopping cart. Watch out Willy, here I came! Where would you put your purchases? Wouldn't have much of a lap on which to set your bags but what fun it would be to have one. $660 - not all that bad!