Haikus are a very elegant pretty, and ancient Japanese form of poetry. Haiku poems must be written in a very rigid way:
It must have 5 syllables in the first line
7 in the second,
and then 5 in the last.
In fact: here's a haiku which explains how the syllables must be arranged:
Haikus must have five
syllables first, then seven
then another five
You can click here to find more about the history of haikus. You can also find many other examples all over the web. Now, apologies to any people that these haikus offend - whilst they stick to the basic rules with regards to syllables, they do not convey the beauty and elegance of real ones. Still, enjoy.