"Conductor," said one, "if that window is opened, I'll just freeze to death!"
"And if it is kept closed," whined the other, "I'll suffocate."
The poor conductor didn't know what to do and finally turned to the GI for help. "What would you do, soldier, if it were a military problem?"
"In the Army we handle such problems like a double-prong attack. Open the window and freeze one of them, then close it and suffocate the other."