A haiku contains three lines. There are five syllables in the first line, seven syllables in the second line and five syllables in the third line. Rhyming is not necessary. Rules regarding word repetition, punctuation and capitalization are left to the writer's discretion.
Haiku is a form of Japanese descriptive poetry. It uses a limited number of words to conjure an image in the reader's mind. Haiku typically observes natural aspects of the world, including seasons, animals, weather and plants. Most often, it is used as a way to celebrate nature. Additionally, it is suitable as a way to introduce children to poetry due to its simplicity.