What is the structure of poetry?

Unfortunately, the question is a little bit too general for a good answer. Different types of poetry have different structures, and some poetry (free verse) is essentially structureless. The only general things that you could say is that poetry is (usually) shorter than stories and novels, and poetry is (usually) a more concise way of writing... poets tend to struggle over finding the perfect _Word_ to describe something, whereas non-poets could write three sentences or more to express the same thing. That's all I can think of that is (usually) true of poetry in general. Some poems rhyme, many do not. Some poems have limitations on Words or syllables in each line. Some do not.