Brooks's poem is unusual in having lines of only three beats and words of only one syllable. The emphasis—if you listen to a recording of her reading it—falls on the "we" at the end of each line in the poem. Brooks changes the line length of the first and last lines to accommodate this emphasis, placing four beats in the first line and only two beats in the final line. Let's take a look at the poem:

We real cool. We
Left school. We
Lurk late. We
Strike straight. We
Sing sin. We
Thin gin. We
Jazz June. We
Die soon.

The first three beats are "We real cool." Normally, the second line would begin with "we," as would the rest of the lines of the poem, but Brooks has structured her verse using enjambment, which is when a sentence doesn't break at the end of a poetic line but instead goes straight into the next line. For instance, "We / left school" is a sentence, but it begins on line 1 and flows to line 2.

What Brooks does is emphasize the "we" and then gives equal weight to the other two words in each sentence. So the meter is "We real cool. We / Left school"—that is, stressed, unstressed, unstressed, stressed, unstressed, unstressed, etc. In her reading, Brooks lengthens the stress on the "we" to make the word sound like "whee," as in "whee, aren't we having fun?" However, the poem ends with a thud on the unstressed words "die soon." Now there is no more "whee": the fun is too soon over.