Separate white cake mix into separate bowls. Blend with different food coloring.
In one pan pour each color into a 9 inch round pan. Beginning with the outside in, gradually pour less. In the second pan do the same steps but reverse the colors.
Bake cakes according to directions. Once cooled begin to stack the cakes and ice with white frosting.
This is where the fun begins...
Make concentric circles with the gel on the top of your cake.
Use a toothpick or skewer to create tie dye design starting from the middle and dragging it towards the outside of your cake.
Ta-Daaaaa! Finished product! Enjoy!