The feds refract prices through their own bent glass.

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The bending creates a lensing effect in the same way that light is bent through glass or plastic in a microscope or your eyeglasses.

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Prof Simon White likens it to the way light is bent as it passes through the lumpiness of an old glass window pane.

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Introduce variations in density into the gas, however, and the waves will be bent and scattered, just as they would be by irregularities in a pane of glass.

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