Grab your Styrofoam cones and pair up like sizes — small cones together and larger cones together. Next, grab two cones of the same size and put them together to form a 3-D diamond shape. Attach to each other using floral pins. You will have three completed diamond shapes, one larger and two smaller.
Roll each of your three diamond shapes in moss and secure with floral pins. Cut off excess and pin down moss ends. Repeat this process until all three cones are completely covered in moss.
Secure one additional floral pin at the top of each cone and cut a long piece of monofilament (about 1 to 2 feet long) to attach to each pin. You can cut the monofilament down to varying lengths later.
Cut three pieces of monofilament, about 18 to 20 inches long, for the three glass ornaments that will be included in your centerpiece. Thread through each ornament and triple-knot it to secure the clear thread. Cut off excess from knot and leave remaining string intact for hanging later.