The pattern is in 'Knitting' by Sandy Black, p95. There is a 'curly' instruction in row 9, that slips 2 stitches to the right and another 2 stitches to the left across one knitted stitch. (slip2 k1 psso, put k1 back on left needle, pass next 2 stitches over, return the st to right needle) I told st-map to k5tog.
Shown with a cast-on count of 33 stitches.