Only 1 color per line : can you fill in the grid ? The concept is super simple, it a bit like a sudoku game: you must fill the grid but you can only place the same color only once on every line. Are you smart enough to play this color game ? color puzzle, logic puzzle, sudoku like, brain teaser, number game, spatial reasoning, color placement, grid puzzle, cognitive exercise, problem solving, mental workout, challenging puzzle, one color per line, brain training, puzzle game