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

I should be able to do nice bell-shaped curves, but it's harder than it looks standing up here; so that's your bell-shaped curve.

我还是挺擅长画钟型曲线的,但站着画真的不太容易,这就是钟型曲线

耶鲁公开课 - 金融市场课程节选

I've shown the differences here in terms of shape, these are shaped liked octagons and these are shaped like squares, but if I looked at these cells, what would I find that's really different about them?

我展示了一些细胞形态上的差异,这些细胞是八角形的,这些是方形的,但如果仔细观察这些细胞,我能找到一些本质上的差异吗

耶鲁公开课 - 生物医学工程探索课程节选