Once upon a time, three men - a lousy Feng Shui teacher, a good Feng Shui teacher and a physicist went to visit an apple orchard. When they were tired, they sat underneath an apple tree. Three apples fell from the tree hitting each and everyone's head.
The lousy Feng Shui teacher later taught his students not to sit under an apple tree otherwise they can be hurt by "apple sha".
The good Feng Shui teacher later taught his students that they must watch out for apples falling down as they were gifts from Heaven. All you need to do is to learn how to "fight apple sha".
The physicist discovered the law of gravity. He is the celebrated Sir Issac Newton.