These are really cool! These color-by-number books are called Querkles and they are part coloring book, part puzzle, and look completely fun!
The author’s name is Thomas Pavitte and here’s a video of him using the same technique in his books, but on a big canvas, to create a portrait of Jimi Hendrix:
Pretty cool, right?!
Such an unusual idea!
You can get Querkles on Amazon for about $10 each.