The effect is an optical trick wrought through a careful recipe.

Unusual paintings with optical tricks hang from the walls.

An optical trick known as forced perspective makes the castle appear even larger than it actually is.

The forms are an optical trick with paint, which defines the seemingly palpable object on successive levels of the glass.

Obviously, a great deal of credit goes to stunt doubles and optical tricks, but the illusion is still astonishingly effective.

These new works, more constructions than paintings, are a riot of disparate parts and optical tricks.

Sometimes it is considered as an optical trick.

It uses optical tricks to obtain a kind of three-dimensional effect, and the colors are rarely reproduced well on photographs.

It uses optical tricks, involving both reflection and refraction, to achieve a high concentration of light.

If they hadn't already seen the first window, they would have thought this was some kind of optical trick.