This square was designed to use striped yarn, but of course you can use anything you wish. :)

The pattern is available in both UK & US terms.

I tend to crochet a bit tighter than average, so your block may turn out larger than 6”. If this is a going to be an issue, reduce your hook and/or yarn size :)

I have also included a short pictorial lesson on blocking. Well how I do it anyway :)