I worked for many years developing engine components. During that time I met and worked with a number of very talented people. One was a dyno tech named Pete. Pete was very good at his job, but he was a practical joker. Because of his talent, Pete often ended up showing the ropes to new techs. On one occasion, Pete was instructing a very nervous new employee about doing dynamometer spark maps. The new guy was shaking in his boots because the engine they were mapping was a one-off prototype that cost close to a quarter million dollars. Pete explained that in order to hear the first signs of knock, it helped to wear head phones. They blocked most of the background noise but still let the high frequency knock through. As the new tech sat at the console with his head phones on, Pete stood beside and just behind him so he could reach the dyn controls if necessary. The test began. As the tech dialed in more timing, Pete produced a box of Tic-Tacs and shook them behind the new-hire's head. He immediately dialed timing out and recorded the knock point. They proceded to the next point and continued the same procedure. Again, Pete shook the Tic-Tacs well before the engine realy knocked. This continued until a complete, but wholy unreal spark map was generated. Then, Pete challenged the new tech to recheck all the points by himself and left the room. Proud of his success and surprised at the ease with which the map was generated, he gleefully began repeating the test. Poor guy tried point after point with no repeat data. Pete (and others) stood outside the dyn room and laughed hartily. When the new tech finally gave up, he emerged from the dyn room with a puzzled look on his face. He was a little ticked off when he found us all laughing at his dilema. But Pete saved the day when he explained that the "new" spark map was indeed the correct one.