Take 4 canvases of each size), paint them a solid base color and add vinyl or stenciled design. stick decals onto canvases, paint the whole thing and then remove the stickers to reveal the wonderful artwork!
Buy a mirror. Put letter stickers on it. Paint over the whole thing. Peel off stickers. (use canvas instead of mirror. Paint canvas what color you want your letters to be first, then letter stickers, paint over, peel off)