An opera is a program* (of opus numbers) whose preimage is scored to its image.Frame arrangement for tuning. (see also opus, developus, opera ludo, hash opera, #opéra-ballet, ballet, #libretto, y-proof)

Note (+): In terms of UUe, I'll usually use an opera to highlight puzzles, namely Egglepple. Generally, an opera will answer the question of 'How?' (as in, 'How to apply machine learning?').