When Gideon had come, behold, there was a man telling a dream to his fellow; and he said, Behold, I dreamed a dream; and, behold, a cake of barley bread tumbled into the camp of Midian, and came to the tent, and struck it so that it fell, and turned it upside down, so that the tent lay flat.
Now Gideon first of all was testing to make sure the angel-let me bring out an offering and he saw the miracle there. Then he put out the fleece and now here's the final thing, he slips down and God confirms that once more. And so there are actually three confirmations to the call of God to Gideon.