Quoted in The Devil's Gauntlet, Os Guiness
Soviet leader Nikita Khrushchev used to tell of a time when there was a wave of petty theft in the Soviet Union. To curtail this the authorities put up guards around the factories. At one timber works in Leningrad, the guard knew the workers in the factory very well. The first evening, out came Pyotr Petrovich with a wheelbarrow and, on the wheelbarrow, a great bulky sack with a suspicious-looking object inside.
"All right, Petrovich," said the guard, "what have you got there?"
"Oh, just sawdust and shavings," Petrovich replied.
"Come on," the guard said, "I wasn't born yesterday. Tip it out." And out came nothing but sawdust and shavings. So he was allowed to put it all back again and go home. When the same thing happened every night of the week the guard became frustrated. Finally, his curiosity overcame his frustration.
"Petrovich," he said, "I know you. Tell me what you're smuggling out of here, and I'll let you go."
"Wheelbarrows, my friend, " said Petrovich, "wheelbarrows."