sentence: Two men exhibit and demonstrate the use of an automated tennis ball server on a tennis ball court. sentence:   An animation graphic appears exhibiting two gold cylinders inside of a metal bracket. sentence:   The animated graphic morphs into a real and actual version of the graphic, appearing on a outdoor tennis court and flanked by two men. sentence:  The two men standing next to the machinery place tennis balls into the machine, which in turn spits out the balls acting as an automated tennis ball server for a player who is standing on the other side of the tennis court with a tennis racket.