Yogācārabhūmi Śāstra, Volume 34 (31)

Original text: 云何观察严具变异无常之性。谓由观见诸庄严具。一时未成。一时已成。一时坚固。一时破坏。见此事已。便作是念。如是诸行。其性无常。余如前说。云何观察舞歌乐事所有变异无常之性。谓由观见舞歌伎乐现在。种种音曲差别。异起异谢。见此事已。便作是念。如是诸行。其性无常。余如前说。

Explanation: How does one observe the impermanent nature of change in ornament matters (alaṃkāra-vastu)? One sees various ornamental implements: at one moment not yet completed, at another moment completed; at one moment sturdy, at another moment broken apart. After observing these phenomena, one has this thought: such volitional formations are truly impermanent in nature. How does one observe the impermanent nature of change in dance, song, and music matters (nṛtya-gīta-vādita-vastu)? One observes the dance, song, and music currently being performed, with their various distinctions of sounds and melodies, arising at one moment and ceasing at another. After observing these phenomena, one has this thought: such volitional formations are truly impermanent in nature.