Possible Clues:

• Quatrain or sestet
• Fixed number of verse lines forming part of a poem
• On it's feet a bit of poetry, by the sound of it
• Is on one's feet on a sound inverse, by the sound of it
• By the sound of it, notwithstanding, a bit of poetry
• There stands a sound a bit inversely, perhaps
• Verse function's variable in appeal
• Group of lines
• There stands a sound, inversely
• Verse produced by extremely smart WW1 soldier, unfinished