One day, a dog went into a meat market.  He stole a piece of meat and carried it in his mouth out of the meat market.  When he arrived at a bridge over a river, he looked down into the water and saw a big piece of meat.  That piece of meat  was even bigger than the piece he had stolen from the meat market and was still carrying in his mouth.   So, he threw the piece of meat he had down into the river.  Then, he jumped into the water after the other piece of meat that he had just seen.  After he jumped into the water, he couldn't see anything at all.  The piece of meat he had seen was just the reflection of the one he was holding in his mouth.  So, the dog ran back to the bridge to look for his first piece of meat, but he did not know to where the water had already carried it away.