Prepare white cake batter; divide into thirds and tint each portion violet, yellow and green, stirring gently. Spray pans with vegetable pan spray. Scoop or spoon different colored batter into pans randomly, filling 1/2 to 2/3 full. Bake 25-35 minutes or until toothpick inserted in center comes out clean. Cool in pan 10 minutes. Remove from pan and cool completely. Crown cooled 6 in. cake layers and stack on cake circle. Crown cooled 8 in. cake layers; position on cake base. Prepare for fondant by lightly icing with buttercream. Prepare for stacked construction.
Roll out fondant 1/8 in. thick. Cover cakes with fondant; smooth.
Tint remaining fondant dark violet, light violet and green with a small amount of yellow. Tint buttercream icing to match fondant; tint a portion of the buttercream yellow.
Roll out light violet fondant 1/8 in. thick; cut 1 in. wide strip long enough to fit around each cake; attach with damp brush. Add tip 5 green buttercream dots around border strip. Stack 6 in. cake onto 8 in. cake. Roll out remaining fondant 1/8 in. thick, cut with round cutouts; attach to sides and top of cake layers. Pipe alternating colors of tip 5 buttercream beads around edges of cutouts. Add tip 5 dots on cake between “flowers.”