Riddle: During WWII, there was a bridge connecting Germany and Switzerland, and on the German side, there was a sentry tower with a guard in it. He would come out every three minutes to check on the bridge, and he had orders to turn back anyone who tried to get into Germany, and shoot anyone trying to escape without a pass. There was a woman who desperately needed to get into Switzerland, and she knew she didn't have time to get a pass. It would take her at least six minutes to cross the bridge, but she managed to do it. How?
Answer: When the sentry went into the tower, she would start to cross into Switzerland, and when he came out, she would start to walk back into Germany. When he saw her, he would tell her to turn back into Switzerland.