Imagine walking along a beautiful mountain stream. You can hear birds singing as the stream rushes by. Light waves of fresh air are cooling your face and the sun warming your back as you keep walking. In the distance you see a beautiful waterfall. You start walking towards this waterfall and begin to feel the mist on your face and hands as you approach it. You can now see the water bounce off the rocks and bubbles of air large and small pop. As you focus on the mist above the waterfall you notice faint appearance of rainbow in the sun.