Once upon a time, there were two leaves floating on the surface of a gentle river. The first leaf had been swept up in the current and was carried along, bobbing up and down as the water flowed around it. The second leaf was still attached to a branch and gently swayed back and forth with the current. As the two leaves floated down the river, they noticed a toad sitting on a rock in the water. The toad looked up and noticed the leaves, and they all floated closer together. "Hello there, my new friends," said the toad in a friendly voice. "What brings you down the river today?" "We've just been floating along, taking in the sights and sounds of the river," said the first leaf. "It's been quite the journey." The second leaf nodded in agreement, its edges rustling softly in the current. "I know what you mean," said the toad. "I've been sitting here watching the river for as long as I can remember. It's always changing ...