In advance: Make mortarboard. Tint 7 oz. fondant black. Mix 1/2 teaspoon of Gum-Tex with 3 oz. black fondant; roll out 3/16 in. thick. Cut a 4 in. square with knife. Let dry on cornstarch-dusted board.
Also: Mold candies. Tint portions of melted white candy green, violet, blue, red and yellow using candy colors. Mold 16 diplomas and 12 caps using piping method. Chill until firm; unmold.
Prepare base board. Cut plywood or foamcore board 1 in. larger on all sides than largest diamond pan. Tint 48 oz. fondant yellow; cover board with fondant.
Bake and cool 2-layer diamond cakes and mini Wonder Mold Cake.
Pipe tip 18 shell top and bottom borders. Attach candies to cake sides with dots of icing. Attach mortarboard to cap with thinned fondant adhesive. Position cap. Tint 2 oz. fondant green; roll out 1/8 in. thick. For cord, cut a 2 1/2 x 1/4 in. strip. For tassel, cut a 1 x 2 in strip; cut 1/8 in. wide x 3/4 in. deep slits for fringe. Roll tassel into a log; attach to cord with damp brush. Cut a 1/4 in. wide strip; wrap around top of tassel. Attach cord to cap. Roll a 3/8 in. ball of black fondant; flatten to form button. Attach with damp brush.
*Combine Christmas Red with Red-Red for red shown. Combine Violet with Rose for violet shown.