Heat oven to 325
Grease bundt pan and set aside.
Make both boxes of cakes mixes. Divide the white cake mix into two bowls.
Color one white mix purple.
Color the other white mix orange.
Pour 2/3 of the prepared chocolate cake batter into a bowl and add a drop or two of black food coloring.
Pour half of the chocolate cake batter into the bundt pan. Pour the purple on top, then the orange, and top it with the remainder of the chocolate.
Do not stir these colors. Just simply place one on top of the other.
Bake as directed on the box (usually about 20-25 minutes) until a toothpick inserted into the center comes out clean. Let cool 5-10 minutes and turn out onto a plate.
Let cool completely, while you make the frosting.
Separate the white frosting into three bowls. Add orange, purple, and black coloring into each bowl.
With a spoon or whisk get one color of frosting. With back and forth motions drip the frosting on top of the cake. Repeat with each color.
Let frosting set and then serve!