The envelope of moving line on the hypocycloid plane may be an epicycloid or cardioid and the...

摆线逆运动中与动切线成定角的直线,渐开线.

Construct rotating nephroid and three-cusped epicycloid while remaining orthogonal to each other.

作旋转的肾脏线和旋转的三瓣外摆线，且彼此维持正交。