Chromadoku

Fill a 9x9 Sudoku grid with colors instead of numbers.

Fill the 9×9 grid so that no row, column or 3×3 box holds the same color twice. It's Sudoku with hues standing in for the digits. Easy, Medium and Hard puzzles. Undo, redo, clear, and a hint when you're stuck. Number badges, 1 to 9 on each color, for shades that blur together or for color-blind play…

Description excerpted from the original listing, which is linked below.