Tint remaining white fondant green and roll out 1/8 in. thick; cut a 13 1/4 x 9 1/2 in. rectangle, rounding off the corners. Position on cake top and smooth edges together. At each corner and at the center of each long side, cut out pockets using the larger opening of tip 1A, remove. Cut matching pockets out of black fondant and position. Smooth edges together. Attach pillars to underside of board at the corners using melted candy.