This image shows a swatch of the basketweave pattern used in Nancy's afghan worked with worsted weight yarn on 4mm needles.
Rows 1-10: K5, (P10, K10) repeat to last 5sts, K5
Rows 11-20: K5, (K10, P10) repeat to last 5sts, K5
I work the afghan 18 blocks tall but you can do more or less as you like - if you want to do a baby blanket, you use single yarn and a size 11 needle - with the baby blanket I do between 10 and 12 blocks.
End with 10 rows of garter stitch.