“Boy Breaking Glass” is in free verse—poetry that lacks a regular rhyme scheme. In terms of overall structure, the poem is nearly symmetrical, with the first and last stanzas comprising six lines, the second and seventh stanzas comprising two lines, and the third and sixth stanzas comprising two lines.

The middle of the poem comprises a fourth stanza of five lines and a fifth stanza of two lines. That arrangement points the reader to the heart of the poem, the struggle between the boy’s voice (represented in the fourth stanza) against the voice of observers, artists, or readers (represented in the fifth stanza). In choosing to give the boy more lines, Brooks spatially represents the importance of recognizing the boy as the authority on his own existence, no matter how oblique his efforts to express himself.

In terms of rhythm, the poem is in free verse, but the lines frequently fall into iambs—an unstressed syllable followed by a stressed one, as in “Whose brok |en win | dow is | a cry | of art ” (Line 1) and “If not | a note, | a hole” (Line 7).