One enterprising group of college students tried to literally manage time, but in the end it came back to haunt them. At this particular university the rule was that if the professor had not arrived in class within the first fifteen minutes of the hour, class was considered a "walk" and the students were free to leave - with no penalties for missing class. The rooms this school were equipped with the old style clocks where the minute hand mechanically ticked ahead after each minute. Some of the students discovered that they could cause the clock to jump ahead one minute if they hit it with an eraser from the black board. The professor of this class was not the most punctual so it became a ritual for these students to take target practice at the clock. After a few well-aimed erasers hit their target, bingo, 15 minutes had passed and the class walked.
At the end of the semester the final exam rolled around. The professor strolled into the room and passed out the test. He said, "You have one hour to complete it." He then proceeded to collect all the erasers in the room and gleefully took aim at the clock. When he had successfully jumped the clock ahead one-hour, the professor called "time’s up" and collected the exam papers.
