The term 'structure put together by a crane' refers to a NEST, which is a four-letter word. A NEST is a structure built by birds, often made of twigs and other materials, and used as a home for the bird and its eggs. In construction, a crane is a large machine used to lift and move heavy objects, and it can also be used to assemble structures. Therefore, a structure put together by a crane could refer to a building or other structure that has been constructed using a crane.