Wheels

Fiorella, who's always stood on her own two feet, put a brave face on it when she had to use an electrified cart to get around the supermark et, but she was horrified when she realized that, after hip surgery, she'd have to use a walker, that universal symbol of incapacity, even if only for a week or two.

On the other hand, the Mars Rover looks like a pretty nifty gadget., like something L. Frank Baum would invent to fly Dorothy to the Red Planet.