So, maybe what you have in mind is some sort of doughnut shape like this that curves on itself, and maybe comes back.

有可能你想到的是一类这样环状物，它自身有这种曲线，也有可能绕回来。

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To make a seawater antenna, the current probe (an electrical coil roughly the size and shape of a large doughnut) is attached to a radio’s antenna jack.

为制作一根海水天线，电流探针（一种电子线圈，尺寸跟形状大致相当于一个大炸面圈）要连接到一副无线电天线端子上。

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Hughes, a British television host and popular historian known for her book on Helen of Troy, does it by concentrating on the shape of the doughnut around the hole.

作家Bettany Hughes是英国电视节目主持人，因为写书《Helen of Troy（特洛伊的海伦）》而为人们所熟知，成为流行历史学家。 她的这本新书就要集中描写“甜甜圈”中的那个黑洞。

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Our closest relatives, chimpanzees and bonobos do not generally form fists, and the researchers think they are unable to: when a chimp curls up its fingers it forms a doughnut shape.

BBC: Fighting may have shaped evolution of human hand

The DIs wore their hair long and pinned up in "sock buns, " a Marine Corps specialty that required snipping off the toe line of a sock, rolling the fabric into a doughnut shape, and wrapping and winding a ponytail's worth of hair around it.

WSJ: Acrylic Nails on the Rifle Range