It took me a while to get this, but to save you having to scratch your head for too long it’s an old optical illusion that plays on our brain’s tendency to see what we want to see. Look at the image close-up and you see the physicist Albert Einstein, but move back a few feet and suddenly it’ll transform into Marilyn Monroe.

The image that Mercedes used was originally created by Aude Oliva Ph.D. associate professor of cognitive science at MIT, who uses images such as this to study how our brains interpret what we see. You can view more of her work over at the Computational Visual Cognition Laboratory.

Apparently our eyes pick up image resolutions with both high spatial frequencies (sharp lines) and low ones (blurred shapes). By blending the high frequencies from one picture with the low frequencies from another, Oliva and her team create images that change as a function of distance and time. We perceive course features quickly, within the first 30 milliseconds, and then absorb the details within the next 100 milliseconds. We also focus on the higher spatial frequencies close up and register softer shapes as our distance from them increases.

Instructions: Click on the image to launch the full size, then stand back and watch it change.

The ad was created by Zapping/M&C Saatchi Spain for Mercedes-Benz Industrial Vehicles and was presumably created for the Spanish market before it was entered into this year’s Epica creative awards, somewhere along the journey the copy was translated into English with an amusing error creeping in to this final version… Have you spotted it yet?