I am going to bread the 100 new thread with this: Given: Four pieces of cardboard. You are told that each one is either red or green on one side and that each one has either a circle or a square on the other side. They appear on the table as follows: 1. Red 2. Green 3. Circle 4. Square Which ones must you pick up and turn over in order to have sufficient information to answer the question: Does every red one have a square on its other side?