Recently I purchased a bunch of mobile puzzle games for my iPhone and one of them was the famous top-rated app "Strata" by Graveck. The rules are simple - you begin with an $n \times n$ board, some squares of which are colored in arbitrary colors. Then you start placing stripes of whatever color you choose over entire rows and columns of the board. Your task is after placing all available $2n$ stripes, the color of every (colored) square to match the color of the stripe which has been placed second over it (on top).
Can you find an easy way to beat every single level of this game?
P.S. You can see a video explanation of the rules in the app review below: https://www.youtube.com/watch?v=NwjyOpA14Vk