You found it This is a stereoscopic 3-D image with a hidden button. To see the 3D effect stare at the two yellow squares on the top of the page and focus your eyes beyond the screen until the two dots become three. Then the 3D image will appear. You might also try putting your face close to the screen so you can't focus on it, then slowly moving back without refocusing your eyes. When you see the 3D image you will know where the button is.