This pattern can be adapted to circular knitting by knitting all the even numbered rows.
Repeat Rows 1 - 20
Row #SideBegin RowRepeatRepeat From *End Row
1R*k4, p2*k4
2W*purl* 
3R*k4, p2*k4
4W*purl* 
5R*k4, p2*k4
6W*purl* 
7R*k4, p2*k4
8W*purl* 
9R*k4, p2*k4
10W*purl* 
11Rk1*p2, k4*p2
12W*purl* 
13Rk1*p2, k4*p2
14W*purl* 
15Rk1*p2, k4*p2
16W*purl* 
17Rk1*p2, k4*p2
18W*purl* 
19Rk1*p2, k4*p2
20W*purl*