Raghunath Mashelkar came up with the lily in the pond theory. He said that it takes a lot of effort for the first perfect lily in the pond. Subsequently, the lily doubles it's number everyday. So on the second day there are two lilies. On the third day there are four lilies and so on. What is important is to know that if the pond is full of lilies in thirty days then on the twenty ninth day the pond is half-full.