The notch of the paraboloid-shaped reflecting mirror is in the face of incident light rays, and the bottom of the paraboloid-shaped reflecting mirror is provided with a first opening.

抛物面状 反射镜的凹口面对入射的光线，抛物面状反射镜的底部具有一第一开孔。

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This container is a paraboloid, but its shape does not need to be made as accurately as a rigid mirror.

ECONOMIST: Mirror, mirror