Hypnotic Tie-Dye Cake

From Nicole Iizuka, POPSUGAR Food

1 6-inch round cake covered in fondant
1 cup powdered sugar
3 tablespoons water
Neon food coloring

Place fondant-covered cake on a wire rack over a pan to catch excess glaze.
In a mixing cup with a pour spout, whisk together powdered sugar and water until a thin, pourable consistency is reached.
Add 1 drop of each food coloring color into the glaze, being sure to leave space between each color. Pour glaze over the top of the cake and let the excess drip off the sides. Let cake dry for 1 hour, or until frosting has set.