A Guidelines' listener who was in a doctoral program at New York University wrote telling about a teacher whose memory will never escape him. The teacher who so impressed him was an instructor at New York City's prestigious Peter Stuyvesant High School. In his classroom hung a 3 x 5-foot flag. On the flag were three black letters against a brilliant background of red, and what was the message? The three letters spelled B-U-T, the adversative conjunction. That's it. When lecturing, this teacher would reach a point where everything that followed hung on one word. That's when he would point to his flag and go on.