I found my blindfold test: simply a series of short poems or fragments that I ask students to respond to without knowing the name of the author. They have to guess whether it's a man or a woman, and guess which side of the Atlantic the poet was born on. I have texts in both Spanish and English. This is my first example:

Log

Then when the flame forked like a sudden path
I gasped and stumbled, and was less.
Density pulsing upward, gauze of ash,
Dear light along the way to nothingness,
What could be made of you but light, and this?

I got the idea from a "name the author" game we used to play with Jordan and Gary and a few others, I believe, on the "subpoetics list" a few years back.