The book started by telling a story about how much distraction we get in our day to day work. It goes on explaining about the concept of “The flow of water”. How the water react when you throw a stone at it. It will create a splash and ripple depends on the mass of the stone. No more and no less. And after the ripples are gone, it will go back to its calm state.
The fourth element of effective thinking is water : seeing the flow of ideas, look back and look forward. There is always more. We need to understand that each invention is an incremental improvement of the previous one.
To adopt this, extend your idea, all idea can be extended. You will need to see the world as it is now in order to be able to look forward into the future.