First time direct drawing on cake

This is the next cake I made. For my husband's friend. And my husband helped me to draw directly on the cake. First, we draw using toothpick. Then we follow the trace using buttercream. Oh yes, I mixed all colors to get black buttercream. It was such a mess. Next time i will only use dark chocolate.

And I think, this time my rainbow layers make the most satisfying rainbow colors. I really like it!