If anyone calls Say I am designing St. Paul's.

The famous, early British mystery writer, E. C. Bentley, was the inventor of the comic verse form after his middle name, Clerihew.  From Wikipedia:

A clerihew (/ˈklɛrɪhjuː/) is a whimsical, four-line biographical poem of a type invented by Edmund Clerihew Bentley. The first line is the name of the poem's subject, usually a famous person, and the remainder puts the subject in an absurd light or reveals something unknown or spurious about the subject. The rhyme scheme is AABB, and the rhymes are often forced. The line length and metre are irregular.

Bentley invented the clerihew in school and then popularized it in books. One of his best known is this (1905):

Sir Christopher Wren

Said, "I am going to dine with some men.

If anyone calls

Say I am designing St. Paul's."

See the entry for other examples such as:

Sir Henry Rider Haggard

Was completely staggered

When his bride-to-be

Announced, "I am She!"

or:

Did Descartes

Depart

With the thought

"Therefore I'm not"?