Let's start with the following scenario:
You are driving along a deserted road late at night. You are several miles from the nearest town and no other cars are traveling this road. Suddenly, you car loses power, the engine dies, and the car rolls quietly to a stop. You note that your gas tank is half full; so you realize there must be something wrong with the engine. You take the flashlight from the glove compartment and open the hood. Your inspection reveals that the fuel line has a small hole leaking gasoline. This has caused the engine to die. You try to call emergency road service, but your mobile phone has no battery life, so you look in your car for tools to repair the leak. All you can find is a ballpoint pen and a drinking glass. How can you use what you have to fix the problem so you can get to the next town? Try to solve this in the next few minutes before reading on.
If, after a minute or two, you haven't solved the problem, consider that broken glass can cut a plastic fuel line and removing the ink cartridge from a pen leaves you with a hollow plastic tube. Think for another minute or two with this information and try to solve the problem before reading on.
Most people will solve this late-night automobile challenge by breaking the glass on the road, carefully using a shard from the glass to cut out the section of the fuel line with the offending hole, and then inserting the hollow pen tube into each end of the ...