I made the largest square I could with the boucle yarn that I had available using the standard basic garter stitch corner-to-corner dishcloth/blanket pattern (for example: this dishcloth or this blanket) by weighing the yarn first, increasing until I had used half the weight, and then decreasing. I then added 4 rounds of double crochet to the edges to bring the size up to the minimum required for the charity that would be receiving the finished blanket.

The skein of boucle did not have a label so I don’t know what it was. Yardage calculations for that yarn is estimated based on info from Bernat Soft Boucle, which was the closest match I could find in my stash.