My children love colouring and drawing, and my son especially loves patterns and tesselation.
I tried searching for pattern books, vaguely remembering having some when I was little (in the 70s). And I found this series and immediately recognised the name and patterns.
This was my favourite pattern book when I was little. The patterns are fantastic, and you can look at them and see different shapes to colour in - eg spirals made out of hexagons etc. The possibilities are practically infinite.
There are only a few different patterns (maybe 5-7?) which are repeated throughout the book, but you colour each one in completely differently so its not a problem.
Its not just for kids either, you could easily while away a quite evening or two colouring in one of these sheets - but if you're a grown up try and stay inside the lines :)
Highly recommended for the little artist in your family. I'll be getting the rest of the series for sure.