An elderly couple dancing in a restaurant while there grandson hides his face.
Some people are in a restaurant.
When Keats looks at the painted figures and trees on the Grecian urn (in Ode on a Grecian Urn), he is not just happy that these apparitions will never fade, because they are art, and thus permanent; he is happy that they have never had to live, that they are not  Ah, happy, happy boughs!