Once upon a time, a strange old man came to a small village. He carried a mixing bowl and a wooden spoon. This sight was odd enough to cause the people of the village to notice what the old man did next. The old man took the bowl to the plowed field next to the village and he put some dirt into the bowl until it was about half full. Then he went to the village pump and filled it with water to about an inch below the brim. Then the old man sat down on a rock next to the pump and began to stir the water into the dirt with the wooden spoon. He stirred and stirred and stirred. The people watched this without much interest until the old man became visibly excited. He peered happily into the bowl and then reached in and pulled out a mud-covered pebble. He then went to the pump and washed it off …