What is "blendoku"

Blendoku is a free puzzle video game for Android and iOS mobile devices. In Blendoku, players are given a grid of squares, some with colors provided, some not. A palette of additional color tiles is provided. To clear a level, a player must "fill in" the empty squares from the palette in such a way as to create smooth sequences of colors both horizontally and vertically. The game includes 475 levels, and additional levels are available as separate purchases.

In July 2013, the creators of the game, responding to the criticism that the game was not accessible to the color-blind, released a solution that would allow the game to be played by individuals with a variety of types of color-blindness.

Kotaku.com called it "Unique and addictive". Gamezebo called it "A brilliantly simple yet challengingly in-depth twist on classic Sudoku".