Musical Instrument Industry: Instrument three-dimensional surface engraving, shape cutting.

乐器行业：可雕刻乐器三维曲面、外形切割。

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Here, you integrate only over a two-dimensional surface, and here, only a one-dimensional curve.

在这儿，只是在一个二维曲面上做积分，这里是一维曲线。

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But the principle of focusing rays through an aperture onto a two-dimensional surface remains the same.

但其原理通过孔径聚焦光线在一个二维表面是保持不变的。

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Picture what it would be like to roll a bowling ball onto the two-dimensional surface of a trampoline.

NPR: Einstein: Relatively Speaking, a Complicated Life

It recommended using geometric lines of latitude and longitude to convey a three-dimensional Earth on a two-dimensional surface, and it included the co-ordinates of over 8, 000 locations in the ancient world.

ECONOMIST: There is no such thing as an objective map

Whether the simplified shape is a sphere or a torus is determined by the behaviour of one-dimensional curves on its surface.

ECONOMIST: Proof of the truth of the Poincar�� conjecture