may I mention a rather common optical illusion which I do not remember to have yet seen in print. If a gothic arch is unequally divided by a space between two vertical parallel lines, these lines ...

According to Encyclopedia Britannica, the illusion occurs when “cross-hatching disturbs the perception of parallel lines.” In ...

Op Art, also known as optical art, is a type of art that features optical illusions ... They are based on geometric designs such as parallel lines, spirals, waves, circles and checkerboard ...

Scientists study optical illusions to learn how the visual system ... Do you see two faces or a vase? Does one line look longer than the other? Do the long lines look parallel?