In order to dye the art board, you should create closed paths with pipes.

When a closed path which does not touch to the sides has empty areas inside, you can also earn stars. This kind of paths will increase the value of your art.

Don't use side pipes unless you have to. You can remove unused pipes on the art board with that way, but it will also decrease the value of your art.

Make your art board turned into a unique masterpiece.