You can't beat a good optical illusion - that one with the old and young woman kept us amazed for hours.
And so we were delighted to discover these dual illusions by Italian artist Fabio D'Altilia. Inspired by Gestalt psychology, they can be seen in two ways - and there's some seriously clever ones in there.
Take a look at the eight images below and give your mind a little exercise.
Images: Fabio D'Altilia