Concrete poetry (or shape poetry) is a poem where the shape matches the content.
Structure
There are no structural rules for writing a concrete poem! So write whatever you want.
Think about what you want your poem to be about and remember that it will need to be something you can also express visually.
Here are some tips for writing your poem:
Write your poem. Keep in mind that shorter poems tend to work better for concrete poems. The longer your poem is, the bigger the shape will have to be.
Pick a shape. It should tell a story as much as the words of your poem.
Draw your shape. Draw the outline of the shape you’d like your poem to take.
Now, you’re ready to add your words to the shape. Remember, you can play with the text, too, by bolding some words, italicizing others, and playing with font size.
Remember: There’s no right or wrong way to make a concrete poem.
Example
Lewis Carroll's "The Mouse's Tale" appears in Alice's Adventures in Wonderland: