Color Switch (4.5/5 stars, all ages, FREE today only as the Free App of the Day) is today’s Amazon Free App of the Day. From Amazon:
Color Switch is a brain bending, tile-based puzzle game.
Tapping a tile switches that tile and any adjacent tiles from light to dark or vice versa. Keep switching until all the tiles are dark and you win! Simple rules, crazy hard game.
Change the size of the board to increase difficulty, anywhere from 3×3 to 30×30 if your device is large enough! Stats are tracked so you can pay attention to your progress and you can choose from six vivid colors.
Different board sizes provide a range of difficulties to attempt
View your stats at any time to continually challenge yourself
Choose your favorite color to make the game more visually pleasing
Control volume with your phone’s hardware volume controls or turn it off in the options menu
Color Switch: get it today, while it’s the Free App of the Day!