Pantoumns

The pantoum is a poetic form from Malaysia.  It began, centuries ago, as an oral folk form.  For our purposes, a pantoum is a poem of indefinite length made up of four-line stanzas; the lines are repeated in a pattern like this:
1
2
3
4

5  (same as line 2)
6
7  (same as line 4)
8

9  (same as line 6)
10
11  (same as line 8)
12

Repeating lines in this way gives the poem a hypnotic or dreamlike effect.

Examples:
Black tron aliens take
Over the earth
They eat all the candy
And do not say please and
     thank you.

Over the Earth 
They fly sky high
And do not say please and
     thank you,
Which is not very polite.

They fly sky high
And shoot lasers,
Which is not very polite.
Then they leave in a rude,
     exciting attitude.
        -Brian Anglin    
http://www.brodbagert.com/pages/view/278/poetry-tips