Chain any number.
Row 1: Starting in the 3rd chain from hook, *YO, insert your hook, YO and pull up a loop, YO and pull through all three loops on hook. Repeat from * to end of row. Ch2, turn.
Row 2: Starting in the 1st stitch, *YO, insert your hook into back loop, YO and pull up a loop, YO and pull through all three loops on hook. Repeat from * to end of row. Ch2, turn.
Repeat Row 2 until you reach your desired length.