Adding Faux Architectural Interest

My husband and I went to a party at our neighbor's house a while back and I loved what the builder did above their fireplace.  They had a nice inset cove that added a lot of detail to the fireplace.  I knew I wouldn't be able to talk my DH into building one in for me, so I decided to paint my own:

I taped off the area where the shadow would be and then using the wall paint mixed with a little bit of black, I painted in a shadow.  After that was dry, I taped off the shadow and added a highlight around it using watered down white paint.  The decor was a work in progress when the picture was taken!  Here is another view of it when entering the room.  People are seriously shocked when they find out it is not real.  When we sold the house, I mentioned that to the buyers during the closing and found out that they thought it was real as well!