In this paper two new cone vertex orbits, which are circle and arc and regular triangular pyramid lines, have been proposed and their complete conditions for exact reconstruction have been obtained.

我们提出了圆加垂直弧段及三棱锥的三棱线这两种新的锥顶轨迹，并研究了以其进行精确重建所需的完全性条件。

youdao

You can see that it goes in, and there's sort of a pyramid or a triangular shape.

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