National Geographic - The National Geographic Society has been inspiring people to care about the planet since 1888. It is one of the largest nonprofit scientific and educational institutions in the world. Its interests include geography, archaeology and natural science, and the promotion of environmental and historical conservation. http://www.nationalgeographic.com/

Oooh that's hard! My screen has value differences (which is what's being tested, not color differences) from top to bottom, and also some from left to right because it's angled. I got 28 but then had a black one and couldn't find it. I tried again with the display centered better, and still got 28 even though they were in a different order. How do you get 33? It stopped at 29 for me.

IFL Science - lots of wonderful science related articles, news, etc. http://www.iflscience.com/

Cute lip art by Laura Jenkinson, make up artist. http://www.laurajenkinsonmua.blogspot.co.uk/