i saw them somewhere a while back,but i can't remember
if you need to simulate wood,try this
lay a base coat or a tan (i use MM Italian Sand) let it dry annd then coat that with Future
when it's all dry take a 1/4 flat brush and dip the tip in Future(lightly) then directly after dip it in some burnt umber artist OIL,,,treat is almost as drybrushing ,a little oil goes a long way,but if you go light and in one direction,it will give a very convincing woodgran,,,,see the sides on the sopwith i did a while back