We are as clouds that veil the midnight moon; how restlessly they speed, and gleam, and quiver, streaking the darkness radiantly! —yet soon night closes round, and they are lost for ever: or like forgotten lyres, whose dissonant strings give various response to each varying blast, to whose frail frame no second motion brings one mood or modulation like the last. we rest.—a dream has power to poison sleep; we rise.—one wandering thought pollutes the day; we feel, conceive or reason, laugh or weep; embrace fond woe, or cast our cares away: it is the same! —for, be it joy or sorrow, the path of its departure still is free: man’s yesterday may ne’er be like his morrow; nought may endure but mutability. –"mutability,” percy bysshe shelley write five to six sentences explaining how the ideas in "mutability” show one or more ideas expressed in "a defence of poetry.” use examples from the essay and the poem in your answer.