illusion mugs, t-shirts and other gifts Free online jigsaw puzzles

Spatial transformations - convex/concave
& Comic Book Picture 8, The Steps Transformed
View Comic-Book Pictures

There are some things that can happen in everyday vision, but not that often. One of them is shown to the upper left, where a leathery shape turns inside out - at upper right it's convex, but at lower left, concave. Just make the edges straight and it doesn't appear to make sense any more, as at lower left. We don't expect plane surfaces to twist like this (though it would be possible, even if very difficult, to contrive a real shape that presented this appearance in perspective).

That makes a point that is fundamental to many illusory realities. Although we seem to take in a global, panoramic view of the scene before us with every glance, our view depends to a far greater extent than we realise on assumptions, for example about what is space and what is solid, based on what we see in a remarkably small area in the centre of our field of view. That's fine in everyday vision, where objects behave in very predictable ways. In pictures they may not be so well behaved at all, and as the eye travels across the scene, our assumptions may be challenged disconcertingly.

This is one of the easiest transformations to construct in your own artwork. Start with the configuration shown lower left here, running right across your picture, and just add contextual detail. It is still not all that simple. Even the smallest details of context, texture or lighting, acting as cues we hardly notice consciously, can enhance the effect in the right place, but spoil it in the wrong one.