In German 60 stitches in the round.rib stitch for 5 rows then knit 2 purl 2 for two rows the purl 2 knit 2 for two rows and repeat these 4 rows for the pattern, finish with rib stitch for 5 rows and bind off.
Start with 3 colors. Each block is 9 stitches so for however wide you want the blanket, count in 9 to get your foundation (always make it an uneven number of "blocks) eg: 19 blocks(makes it about long) stitches then add 4 sc for the foundation row.
Knitting Tutorial - Matress Stitch worked horizontally to join two pieces of knitting. The stitches are in contrasting color to show detail, but it might be fun to do this and add some embroidery for embellished seams on a sweater. from Knitting Daily