Concrete

Concrete poems—sometimes called ‘shape poems’—is poetry whose appearance matches the topic of the poem. The words form shapes which show the poem’s subject as a picture, as well as through their literal meaning.  This type of poetry has been used for thousands of years, since the ancient Greeks began to enhance the meanings of their poetry by arranging their characters in visually ways back in the 3rd and 2nd Centuries BC.

example from http://www.poetry4kids.com/blog/news/how-to-write-a-concrete-poem/