How do participants in multi-party conversations project and coordinate the timing and content of their gestures when such gestures are exchanged simultaneously? This paper considers examples of the Simultaneous Gestural Matching (SGM) of spontaneous gestures to examine gestural coordination during conversation. Detailed analyses show that (1) the first utterance of an adjacent pair projects the timing and content of the subsequent gesture; (2) the first recipient initiates a gesture unit or a phrase to respond to the first part of the pair; (3) the other recipients provide gestures that synchronize with the gesture of the first recipient; (4) the parties focus their eye movements on monitoring the gestures made by other participants; (5) the parties control the micro-timing of the gesture phases in the gesture unit or the phrase; and (6) the entire SGM process enables differences in gestures to reveal differences among the parties in terms of their knowledge about the topic. We constructed a simple model of SGM for purposes of further discussion.