Blend cake mix with eggs, oil, and buttermilk. Spoon ½ cup of batter into four separate bowls. Tint each bowl a different color, set aside. Divide remaining white batter between two greased and flour cake pans. Drop spoonfuls of tinted batter randomly over the white batter. Gently pull tip of a knife through batters, creating a marbling effect.

Bake in a preheated 350 degree oven until golden and an inserted toothpick in the center comes out clean; approximately 28-31 minutes. Cool cakes completely.

Trim the tops of the cakes, leveling them. Sandwich the layers together with frosting and set on serving plate. Spread remaining frosting over sides and top of cakes. Using photos as your guide, pipe concentric hexagon shapes of different sizes and colors on the sides and top of the cake. Gently pull the tip of a toothpick through the frosting (not the cake), starting in the center of the gel circles. Randomly dot the cake with SKITTLES® Brand Bite Size Candies.