To the average person on the street, Robin Hood was a guy who "robbed from the rich and gave to the poor." To the archery hunter however, a Robin Hood is when you shoot two arrows in exactly the same spot so that the second hits the first and goes inside it - making one very long arrow. It might be fun to do - once or twice - and it looks pretty impressive, but it gets a little expensive when good arrows cost anywhere from $6 to $10 each. Even if an arrow is not hit exactly in the center, a vane can be ruined or a nock broken by a 'near miss.' Either way, something has to be replaced, which costs both time and money.
For the average bow hunter a simple solution to this is to use a target that has a number of different bull's-eyes on it. By shooting only one arrow at each bull's-eye, you greatly minimize the chance of hitting one of the previously shot arrows. Try to hit the very center of your bull's-eye with each arrow, of course, but save your arrows for hunting, and save some money at the same time.