Today's poem by Miroslav Holub (1923-98) is square, having 5 lines of 5 letters each; it describes the letter M by using what is "not M" -- a style of reasoning often used to good effect in both poetry and mathematics.
Very Brief Thoughts on the Letter M by Miroslav Holub
A, b, c, d, e,
f, g, h, i, j,
k, l, n, o, p,
q, r, s, t, u,
v, w, x, y, z.
“Very brief thoughts on the letter M” is from Miroslav Holub's collection, Notes of a Clay Pigeon (Secker and Warburg, 1977) and is found with a selection of other poems by Holub at the Poetry Foundation website. Czech poet Miroslav Holub was also a noted research scientist (immunologist); for additional poetry by Holub, you may visit also these postings: December 9, August 19, April 28, and March 30.