preheat oven to 375°F

combine both cake mix into one large bowl and mix according to packaging directions. then divide batter into six equal parts in six different bowls

add about 1/4 tsp of six differnt liquid food colouring to each of the bowls. each bowl gets a different colour. i used yellow orange red purple blue and green. mix colour thoroughly.

grease pan and line with wax paper. i used and 8'inch circle pan.

pour in one of the coloured batter and bake for 15-20 mins or until a tooth pick comes out clean when inserted. remove the baked cake from pan and put on a flat surface to cool. re-grease and line the pan and bake another colour batter. follow the step until all colours are baked. after cooling completely i suggest putting all six cakes into the fridge for 2 hrs to make icing easier.

use your serving plate and place a tsp of icing in the middle. place the purple cake on plate. use a thin layer of icing to cover the top of the cake then place the red. repeat the step with a thin layer of icing before placing the orange, yellow, green and then the blue on top. when all six cakes are stacked, icing all around the cake until cake is completely covered.

this step is optional. to decorate the cake you can use the topping of your choice. i used coloured sprinkles all over the cake.