这些塔，或称“叶片”，围绕着一个三角形中心轴旋转，中心轴承载着电梯和机械设备。

These towers, or "blades," pinwheel about a triangular central shaft that holds elevators and mechanical equipment.

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经过八角形的中心画两条直线，能够得到六个一样的三角形。

Six identical triangles can be formed by drawing two straight lines through an octagon's center point.

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随后将获得三条粗略定义的角边，用于定义指向图像中心的近似的等边三角形。

Three roughly defined corner edges are then acquired that define an approximately equilateral triangle pointed at the center of the image.

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So it's trigonal because we have these three atoms that are bound to the central atom here, and if you picture it, it's actually shaped like a pyramid.

这里三角形是因为,我们有3个原子核中心原子成键，如果你画它，它就是金字塔形的。

麻省理工公开课 - 化学原理课程节选