How many lines does a poem have? There's no minimum and no maximum. A one-line poem is hard to imagine, but not impossib
Hero and Leander is the Greek myth relating the story of Hero (Ancient Greek: Ἡρώ, Hērō, pron. hay-rō (ancient) and like "hero" in English), a priestess of Aphrodite who dwelt in a tower in Sestos on the European side of the Dardanelles, and Leander (Ancient Greek: Λέανδρος, Léandros), a young man from Abydos on the opposite side of the strait. Leander fell in love with Hero and would swim every night across the Hellespont to be with her. Hero would light a lamp at the top of her tower to guide his way.
Succumbing to Leander's soft words and to his argument that Aphrodite, as the goddess of love, would scorn the worship of a virgin, Hero allowed him to make love to her. These trysts lasted through the warm summer. But one stormy winter night, the waves tossed Leander in the sea and the breezes blew out Hero's light; Leander lost his way and was drowned. When Hero saw his dead body, she threw herself over the edge of the tower to her death to be with him.
Poetry analysis is the process of investigating a poem's form, content, and history in an informed way, with the aim of heightening one's own and others' understanding and appreciation of the work.
The words poem and poetry derive from the Greek poiēma (to make) and poieo (to create). That is, a poem is a made thing: a creation; an artefact. One might think of a poem as, in the words of William Carlos Williams, a "machine made of words". Machines produce some effect, or do some work. They do whatever they are designed to do. The work done by this "machine made of words" is the effect it produces in the reader's mind. A reader analyzing a poem is akin to a mechanic taking apart a machine in order to figure out how it works.