The poem is a haiku.
A sonnet has 10 syllables per line.
A limerick has five lines, where the first, second and fifth lines must have seven to ten syllables with the same rhyme scheme and verbal rhythm, and the third and fourth have five to seven syllables, of a different rhyme scheme and verbal structure, but are the same of each other (aa-bb-aa).
And a free verse does not follow any poetic device rules, really, they are free of limitations and usually do not have any particular rhyme scheme or verbal rhythm.
