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Lunette means "little moon" in French but in English describes the architectural element of a half moon that is used for windows or decoration in architecture. This photograph is actually an arched lunette because the top is pointed. The black & white checkered pattern of the bricks can cause an optical illusion of movement because the pattern remains on the retina while the eye is continually making slight adjustments so you are not seeing the picture moving but experiencing your own eye movement. This is always going on but not noticeable in most situations.

So my vision is not so bad.