We've seen plenty of mind-blogging optical illusions over the years, and it's fair to say we'll always have room for one more. But almost every illusion we see is impressive (the human brain is quite a thing), it's not every day we see one that's also carrying an important message.
Titled They Can Disappear, this illusion by Russian artist Ilja Klemencov was created for the World Wildlife Fund for Nature (WWF), and features the organisation's iconic panda logo (arguably one of the best logos around) – you'll just have to squint to see it.
Stare at those zigzag lines for long enough, and you might eventually be able to make out the shape of the Panda. Klemencov's design is an example of an illusion known as the McCollough effect. Discovered in 1965 by Celeste McCollough, the illusion is a "phenomenon of human visual perception in which colourless gratings appear colored contingent on the orientation of the gratings," (thanks, Wikipedia).
But while the illusion itself is as brain-frying as any other, perhaps the most impressive thing here is how the very concept of the elusive image lends itself to the organisation's urgent message. Indeed, the 'disappearing' animal is a grimly ingenious visualisation of an endangered species.
While this particular design isn't new (according to Sydney Morning Herald, it took first prize in the 2010 World Student Poster Biennale in Serbia), it reliably does the rounds online every few months. With the clever message, it has to be one of our favourite optical illusions out there.
From From retro head-spinners to brand new colours, we've seen some truly incredible illusions lately. If you fancy creating your own, take a look at the best Adobe Creative Cloud deals below. And for all of our favourite mind-bogglers in one place, check out our 12 favourite optical illusions.