Multiple of 3
In the 2nd chain from the hook, work 1 HDC and 1 DC. *Skip two chains. In the next chain work SC, HDC, DC. Repeat from * across the row until there is one chain left. Work 1 SC into the final chain. CH 1 and turn.
Work 1 HDC and 1 DC into the top of the SC of the previous row. *Skip two stitches, then SC, HDC, DC into the next stitch. Repeat from * across the row ending in the last stitch with 1 SC. CH 1 and turn.
REPEAT ROW 2
See video tutorial below.