epicycloid

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

逆运中与切成定角的直,其包络也是圆周渐开.

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

作旋转的肾脏和旋转的三瓣，且彼此维持正交。