It isn't the kind of doughnut-shaped, the rich inner and poorer outer, that Paris has.

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That technique uses a magnetic field to hold large volumes of the same isotopes of hydrogen inside a doughnut-shaped vessel, called a tokamak.

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The muscular contraction creates vortices doughnut-shaped rings of water below the creature's body.

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Paul Andreu designed the first terminal at Charles de Gaulle, north of Paris, as a doughnut-shaped structure with glass tubes crossing through the middle, but when it came time to expand the airport, in the nineteen-eighties, only a few years after the first part was finished, his futuristic form seemed more like a cartoon than like a functional building, and more conventional terminals were ordered up.

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Still others have bent cucumber shaped pistons zooming back and forth in a huge, hollow cast-iron doughnut.

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