Cool optical illusion disappears when you get close

If you’re like me, against a backdrop of red and purple, you see alternating squares of blue and green.

Lean in real close to your screen — or download the image to your own computer and zoom in on Photoshop – and you’ll see that the “blue” and the “green” are actually the same colour.

There’s a spiral version of the same illusion here, but because it’s a jpg, you can’t zoom in endlessly like the one I’ve posted.