Limerick of London’s Bridge

A limerick‑encoded stanza (AABBA) — empire, saboteurs, and a song called “Castle.”

There once was a bridge in the dark,
Whose stones bore an empire’s mark.
Irish saboteurs sang,
“Castle” rose as it rang,
And London fell mute at the spark.

This stanza is both playful and pointed: Limerick the city, limerick the form. A song as a key; a chorus as a circuit‑breaker.