Here's why:
* Narrative: The poem tells a story about a boy named Jack who wants to be a pirate. It follows a sequence of events, starting with his request to his mother and culminating in his disappointment.
* Humor: The poem uses humorous elements like Jack's absurd requests (a wooden leg, a parrot, and an eyepatch) and his mother's practical responses.
* Whimsical tone: The poem has a light-hearted and playful tone, making it engaging and relatable for children.
While it doesn't fit into a specific type of poetry like a sonnet or haiku, "Jack" is a great example of Shel Silverstein's style, known for its simple language, imaginative scenarios, and humorous approach to everyday situations.