Actually I think it is better to show a random poem. Novels are long, and opening lines can easily trick you to think that you "know" the works. But poems, on the other hand, can be short (and long), with more vivid language in just a few lines.
You can have short poems (The fog comes / on little cat feet./ It sits looking / over harbor and city / on silent haunches /and then moves on.) or a passage of long poems (I saw the best minds of my generation destroyed by madness, starving hysterical naked,/ dragging themselves through the negro streets at dawn looking for an angry fix).
You can have short poems (The fog comes / on little cat feet./ It sits looking / over harbor and city / on silent haunches /and then moves on.) or a passage of long poems (I saw the best minds of my generation destroyed by madness, starving hysterical naked,/ dragging themselves through the negro streets at dawn looking for an angry fix).