Reader's Digestの定番記事 "Laughter The Best Medicine" 11月号からの引用です。
A crafty young bard named McMahon,
Whose poetry never would scan,
Once said, with a pause,
"It's probably because I'm always trying to cram as many extra syllables into the last line as I possibly can.
" "scan" は日本語にもなっているスキャナーの動詞ですが、それに対応する日本語の「走査する」の意味ではないですね。辞書を見ます。
・Macmillan Dictionary: literature if poetry scans, it has a regular rhythm (=pattern of beats): These are poems that neither rhyme nor scan.
・Merriam-Webster's Online Dictionary: to conform to a metrical pattern: this poem scans well
・Cambridge English Dictionary: specialized literature If a poem or part of a poem scans, it follows a pattern of regular beats: This line doesn't scan - it has too many syllables.