Kolrosing is a very old method of giving fine line surface decoration to wood, simply using the tip of a belt knife to make cuts and then rubbing coal dust into it to bring out the Pattern. The Scandinavian tradition used it to decorate spoons, small bowls, boxes, cups, etc. The designs were more geometric or Celtic in origin, but anything which can be drawn with a pencil can be done. It is like in the early years where you are to follow the lines. "O Boy" that is tough when the knife wants to follow the grain of the wood. I used a Kolrosing knife and used espresso grounds to rub in the lines. Then I coated it with mineral oil and then a wax.