EDIT: There are two random stitches in the forehead of the skull that should be knit stitches, but don’t have a symbol in the chart. I have no idea how I managed to miss that for all this time. Until i get it sorted, please note that the chart has these errors. Thank you!
The cable is show here in bulky weight yarn on the sweater and worsted on the swatch below..
There is some cabling done on the wrong side of the work. Don’t forget that part! You can do one skull or stack as many as you wish.
As usual for cables, it will show up best in a plied yarn and since it doesn’t stand out from the background much, in a lighter yarn.