Fantastic Bill. That's a lot of detailed work you've done for a cold air return. I'd like to place an order for twenty-five and I need them in four days ... Ha, ha. A very fine job well done.
This type of art I enjoy very much Paul is called double bevelled marquetry (painting with wood). If you search on the net and type in double bevel marquetry you'll find a great selection of instructions along with videos demostrating this type of art. I use a wide selection of exotic hardwoods for my colours (1/8" in thickness). I do mostly scenes and or animals so my backboard I bevel my hardwoods into are â…›".
Scroll down to Mathew Wermer Demonstrates Double Bevel Marquetry. He gives a demonstration very close to the procedure I use. Hopefully this will give you a start. Let me know if I can be of further help.
The over lapping heart on cross and heart shaped base is unusual from what I've seen for crosses. A overall very effective pattern and your work in cutting and finishing is fantastic. Well done.
Great sign work as usual Kevin. Have you done poems, quotations, scriptures and etc.? Thinking of additional sales for you since your work is excellent and you enjoy what you do.