I had a lesson this morning. When I arrived, my pro left the court and went out to his car. When he returned, he was carrying The Contraption. It was a yellow, metal thing sitting on a fixed triangular base. It reached upward, and it had a tennis ball mounted and suspended about three feet over the ground. The tennis ball was on a rubberized appendage so that if you hit the tennis ball the arm would bend forward and then return to its upright position. The tennis ball rotated freely. Anyway, pro explained that the contraption was going to help me improve my topspin. He demonstrated his FH, putting the tennis ball in his contact point and hitting/brushing up on it. The idea was to get a lot of brushing and little forward movement. If you drove through the ball, it would whip violently forward on its rubberized appendage, and that is bad. He was trying to get more of a windshield wiper motion out of me. He had me hit multiple reps, with him watching closely and making little adjustments until everything was perfect. Then I hit real balls. Dang. I have been struggling with controlling topspin and producing a ton of it when I need it most -- short angles. I just couldn't get the hang of whatever needs to be done to get sick topspin and really shape the ball trajectory at will, especially when close to the net. After a few minutes with The Contraption, I was doing it. From the baseline off of live balls, I could rip short angles that I didn't think possible. We then repeated the whole drill on the BH side. This was a little less successful, but there was measurable improvement. Has anyone ever used The Contraption as a student or as a teacher? 'Cause I don't know what he paid for it, but that thing is worth the money!