There are 8 pills. They are all of the same size and colour. One pill weighs slightly more and is poisonous. You have a balanced scale and can only use it twice. How can you find the poisonous pill? You have eight balls all of the same size. 7 of them weigh the same, and one of them weighs slightly more. How can you find the ball that is heavier by using a balance and only two weighings?