A lot of folk have asked "What the heck are those things on your back wheels?" when they see Olivia for the first time.
They're wheel hub winches. The simplest form of getting out of a sticky situation. Straps attach with pins to the barrel shape on the back wheels, then to a third point - and "roll up" as you go, moving you out of whatever you've got into. Well, that's the theory anyway. I really only found out about it myself after spotting an explaination in a LRO magazine.
Yesterday I took some pics for a friend who's interested in trying to make some, so thought I'd share.