Optical illusions are confusing for most people ... posts in huge numbers and asking their followers to find the curved line which keeps changing as you look away from it. If you haven’t ...

The image is given structure by a contrasting geometric line – the white outline of a circle in the background. Organic lines dominate this poster advertising salad dressing, Delftsche Slaolie ...

but they're all geometric shapes that we wouldn't be able to physically create. These cubes give the illusion of being a real shape, but there's always at least one line running both in front of ...