An attempt to get a moire-like effect without pre-preparation, using the grain. Oak (in fact a piece of old fence-post) with black stain and limed wax finish. The finish gets somewhat greyed by the liming but the effect is still quite interesting I think. The brass candle holder is sunk into the end - it is quite deep with a cone and 24mm barrel and the space is drilled at the start, with a 24mm wooden plug then inserted to allow turning between centres (including the conical hole for the holder, cutting in to the disposable plug).
One could use ammonia darkening but this would probably count as preparation!