Gershwin himself played the piano part of "Rhapsody in Blue" at the concert.

VOA: special.2009.02.15

As we come back in to this, I think we've got a situation where the piano keeps playing the four-note motive, the part like he was building it up for tension.

回到这里,我想情况是这样的,钢琴一直弹奏着四音节的动机,这个部分像是钢琴在制造紧张气氛

耶鲁公开课 - 聆听音乐课程节选