Take a stitch Tuesday
This is the double lock stitch. Instruction can be found at http://pintangle.com/2014/09/09/take-a-stitch-tuesday-129-and-130-lock-and-double-lock-stitch/ It isn't very different from the Lock stitch other than it is done on both sides of the the straight stitches. Mine looks a little messy. I think a thicker thread would make it look nicer.