Well...look at my first try at making a rainbowcake. It's decorated with simple sugar icing and some Haribos :)
I made normal dough and seperated it in different bowls to mix the colors with food coloring. Then I started putting the dough in the spring form, always a few spoonfulls into middle.
That's how it looks. I made the mistake of always adding only two teaspoons...so the lines got very small and after baking looked very faint because they blended together.
Well, I learned from my mistake and I hope next time the cake will turn out better .