A boy was rushed to the hospital emergency room. The ER doctor saw the boy and said, "I cannot operate on this boy. He is my son."
But the doctor was not the boy's father. How could that be?
Four cars come to a four way stop, all coming from a different direction. They can't decide who got there first, so they all entered the intersection at the same time. They do not crash into each other. How is this possible?