I came up with this pattern a while ago.
Cast on 12sts.
Row 1: P.
Row 2: K2tog, k to the last 2sts, k2tog. (10)
Rows 3-8: Repeat rows 1-2, three times. (4)
Row 9: P.
Row 10: K2tog, twice. (2)
Row 11: P2tog. (1)
Finishing: Roll the triangle into a croissant shape and secure it with few stitches. Sew the edges together.
I think these would look really cute in a picnic setting.