Square poems -- pricked by a cactus!

     Back home now in Maryland after some time in Arizona (near Tucson) with cousins, my mind is full of the beauty and diversity of the cactuses that I saw there -- in yards and gardens and, most spectacularly, at the Arizona-Sonora Desert Museum (BIG Thanks, Bob and Ann!)  My interest in these prickly plants led me to seek a poem that featured them.  What I found is a small "square poem" in my article "Mathematics in Poetry" -- published several years ago by the Mathematical Association of America (MAA) and available here.  Below, I quote that tiny square poem -- preceded by an explanatory introduction.

Mathematicians enjoy pushing against constraints to find what is possible despite their presence; I enjoy a similar struggle in poetry. For example, when I wanted to write about my decision to be polite even though somewhere inside I feel very uncivil, the constraints of a 3 × 3 square poem led me to:

Mock feelings
serve as well
as true ones.