9" x 13".
Use worsted weight yarn and a size J/ hook, or your own preferred hook and yarn.
Row 3: with black, ch 5 (counts as first dtr), and work the following sts across row: dtr, tr, dc, hdc, sc, hdc, dc, tr, dtr, dtr, dtr, tr, dc, hdc, sc, hdc, dc, tr, dtr, dtr. Turn.
Row 4: ch1, sc in each st across. join white at the end of row 4. Turn.
Repeat rows 1 - 4, five more times. Fasten off black and white at the end of row 20.
To make the border, you will need to work sc all around the outside edge of blanket. Work 3 sc sts in each corner st, and space your sts evenly along the rough edges, so that blanket lies flat. After working once around, sl st to join and ch 1, turn. Work a round of sc again, still working 3 sc in each corner st. Join at end of rnd and fasten off blue.
It is pretty easy to adapt this style of pattern to make a larger blanket, pillow cover, scarf, etc. Just work sc through dtr to change the height of your sts. You can make the "wave" longer or shorter by using different combinations. Every even row, work sc back along the sts. Then, match up all the sc with dtr, hdc with tr, and dc with dc.
Enjoy and have fun with it!