Nature vs Human Arrogance
Shelley makes Ozymandias look absolutely ridiculous through dramatic irony. The king boasts "Look at my works, ye mighty and despair," but ironically there's "Nothing beside remains" - just empty desert stretching endlessly.
The consonance in "boundless and bare" and "lone and level sands" slows down the poem's pace, making us feel the vast emptiness where Ozymandias's empire once stood. Nature has completely erased his so-called mighty kingdom.
Both poets break their poetic forms to show loss of control. The Duke's iambic pentameter cracks when he gets angry about his "nine-hundred-years-old name," and the extra syllable reveals he's actually losing it. Meanwhile, Ozymandias is written as a sonnet (usually about love) but ironically shows the opposite - the destruction of someone's self-obsession.
Key insight: When the poets break their structured verse forms, it mirrors how the characters' power is also breaking down.