"If this window is open," one declared, "I shall catch cold, and will probably die."
"If the window is shut," the other announced, "I shall certainly suffocate." The two glared at each other.
The conductor was at a loss, but he welcomed the suggestion of a man sitting nearby:
"First, open the window, conductor. That will kill one. Next, shut it. That will kill the other. Then we can have peace."