The board's grid provides plenty of pin holes for stretching granny squares as taut as need be, and the pins are long enough to stack multiple squares leaving space between them for airflow. Leave the squares in place until dry, then remove the pins and admire your newly well-behaved, flat squares that will now be much easier to stitch together!
Works equally as well for knitters dealing with stubbornly curly gauge swatches. A flat gauge swatch is much easier to measure!
