Crocheted mitered square - my own pattern (sort of)

I've loved mitered squares since I saw my friend Aileen making a shawl out of them. But she is mainly a knitter, and I am really a crocheter, so I decided to search the Web to see if I could find a pattern for a crocheted mitered square. None met with my approval, but I got the gist of what one was supposed to do, so here is the result. It took about an hour, and surprisingly, no frogging was involved in the manufacture of this potholder.

So for you crocheters out there, here is how I did this:

Chain an even number of stitches, plus one at the end (for single crochet). I crocheted 40 + 1.
Single crochet in 2nd chain from hook, single crochet the first 18 stitches, single crochet together stitches 19 and 20, and also 21 and 22, then single crochet the rest of the row.
Continue to decrease the middle four stitches in each row.
I ended by doing a single crochet border (two times) around the outside - this seemed to help maintain more of a square shape.

Ta dah.