A) The Lucky Cinder-Block is a fictitious object carried
by backpackers and students. It represents any extremely heavy object carried
for no particular reason.
B) Any useless, weighty, or otherwise pointless object
occupying an inordinate amount of space
in a backpack.
Steve: Hey Joe, Why is your backpack so heavy?
Joe: I don't know.
Steve: Dude, you brought your lucky cinder-block
along didn't you?