Making Brusts of Colors in Milk Tray

Cleary the food we eat contains fat which normally sticks to the dishes we use. Furthermore even whole milk contains fat. But how did the colors interface when they were separated? How did the soap affect the food coloring???Well basically when I dropped the liquid soap onto the tray, it tried to break down the fat in the milk. While it was doing that, it caused the colors to mix and join into each other and swirl around in the tray.

What liquid dish soap works the best?

I clearly think that it should be liquid and not a bar of soap because when the soap is trying to break down the fat if it was a bar of soap the soap in the chemicals would just react to the food coloring because it was not powerful enough to break the fat. In that case the colors would stay in its place.

Does the shape of the tray affect the reaction?

Defiantly on the size because if it was to small the colors would easily interface toghter and the soap would try to break down the fat react to the chemicals in the food coloring.