Trees and Forests
One of my nieces' favorite games is a guessing game. One person thinks of something, and the other player tries to figure out what that something is by asking only yes or no questions. If you have played this game before, you have probably seen the following pattern in action: first ask questions that eliminate large categories of possible answers, such as "Is it an animal?", and progressively narrow down the focus of the questions as you gather more information. This is a more effective strategy than asking from the get-go, say, "Did you think about a zebra?" On the one hand, if the answer is "yes," you are done, as there is only one possible answer. On the other hand, if the answer is "no," you are in a rather bad spot, having learned essentially nothing.