Color Squared: Color, Dot, Dash, or Stamp Your Way to Pixel Art by Lee Meredith
Coloring books for grown-ups are super popular these days. This is a take on those, but each image is a grid with a number or letter in each square. You fill those squares in using your tool of choice and, gradually, a pixelated image will appear. Instructions are included for using different ways of filling in the squares, such as drawing circles, lines, or dots. A basic monotone image is included for each coloring page, showing what it would look like if you filled each square fully using greyscale.
full disclosure: I received a review copy of this book from Blogging for Books