Do It Yourself Dome-Shaped Clear Christmas Ornaments. Decorate these ornaments inside or out for a creative do it yourself Christmas craft project. Fun for any age, these plastic ornaments are just as fun to decorate as they are to decorate your Christmas tree or elsewhere in your home. We recommend using crayons, colored pencils, washable markers, permanent markers or acrylic paint, sold separately online. (1 dozen per unit) 3 1/4" Plastic.