"JNugent" wrote in message
...
Do rucksacks also have hardened steel sharp bits sticking out and/or
covered in black grease as well?

Do unicycles?

If they operate in the same way as bicycles, the answer must be "yes".

Well, they're a pedal driven wheeled vehicle. But does that cover your
definition of 'operated'? Because the answer is certainly "no".

Not that you see too many of them.

There's an entire internet out there full of useful information - you have
my permission to go and learn.

(never been to the circus?)

clive