Such a long dog

　　Once there was a blind man. One day when he was walking, he stepped on the head of a dog who was sleeping. The dog barked for a while.

　　The blind man went on for miles, this time he stepped on another dog's tail, so this dog also barked.

　　The blind man had thought that it was the first dog, so he said in surprise: "It's a wonder that the dog is so long."