A bloke is sitting by his car at the side of the road looking unhappy. A passer-by sees his glum face and asks what the problem is.

"I've locked myself out of my car." replies the man.

"That's not a problem," replied the passer-by, "Step out of the way, and let me have a look."

The motorist is a bit perplexed, but reckons there's no harm in it letting the man try. So the passer-by turns around, and rubs his legs slowly up and down the driver"s door. Suddenly, the lock opens and the man turns and opens the car door.

"That's amazing!" says the motorist, "How did you do it?"

"It's easy," replies the pedestrian, "I'm wearing khaki trousers."