Étude No. 19 in C-Sharp Minor, Op. 25 No. 7 - Etude No. 21 in G-Flat Major, Op. 25, No. 9,"Butterfly's Wings" (Live) (升c小调第十九号练习曲，Op. 25 No. 7 - 降G大调第二十一号练习曲，Op. 25 No. 9《蝴蝶的翅膀》（现场版）)