A man is strolling past the mental hospital and suddenly remembers an important meetingUnfortunately, his watch has stopped, and he cannot tell if he is late or not Then, he notices a patient similarly strolling about within the hospital fenceCalling out to the patient, the man says, "Pardon me, sir, but do you have the time?"The patient calls back, "One moment!" and throws himself upon the ground, pulling out a short stick as he does He pushes the stick into the ground, and, pulling out a carpenters level, assures himself that the stick is verticalWith a compass, the patient locates north and with a steel ruler, measures the precise length of the shadow cast by the stickWithdrawing a slide rule from his pocket, the patient calculates rapidly, then swiftly packs up all his tools and turns back to the pedestrian, saying, "It is now precisely 3:29 pm, provided today is August 16th, which I believe it is"The man cant help but be impressed by this demonstration, and sets his watch accordinglyBefore he leaves, he says to the patient, "That was really quite remarkable, but tell me, what do you do on a cloudy day, or at night, when the stick casts no shadow?" The patient holds up his wrist and says, "I suppose Id just look at my watch"