sentences:  Also featured strongly in the track is Joe Satriani's fluid and complex usage of the legato technique to quickly play scalar runs.When played live, the intro feedback is produced by Satriani and then manipulated by physically moving himself and his guitar to different positions relative to his amplifier - this changes the frequencies of the feedback, giving an interesting array of variations on the initial feedback.Satriani knows where the harmonics are generated on each separate stage on tour by "mapping them out" during soundchecks and marking the physical points on-stage with tape.