A rich American went to Paris and bought for a lot of money, a very strange picture painted by a fashionable modern artist. But when he came to his hotel and wanted to hang the picture up on the wall, he could not tell which was the top and which the bottom of the picture.So,he thought of a plan:he invented the artist to dinner.When he began to eat,he looked to the picture many times.After some time,he understood that the picture was upside down."Why, my friend", he said, "my picture is hung upside down". "Oh, is it?" said the American. "Why didn't you tell me so at once?" "Well, you see, I was not sure myself at first", said the artist.