1、A circle that rolls around another circle; generates an epicycloid or '.
繞著另一個(gè)圓圈滾轉(zhuǎn)的圓圈；產(chǎn)生外擺線或內(nèi)擺線。

2、Construct rotating nephroid and three-cusped epicycloid while remaining orthogonal to each other.
作旋轉(zhuǎn)的腎臟線和旋轉(zhuǎn)的三瓣外擺線，且彼此維持正交。

3、The envelope of moving line on the hypocycloid plane may be an epicycloid or cardioid and the…
擺線逆運(yùn)動(dòng)中與動(dòng)切線成定角的直線，其包絡(luò)也是圓周漸開線。