It creates as a distance between two points, rather than a straightline, an arabesque.
它加长了两点之间的距离，使它变得非直而曲。
2
A tangent is a straightline that just touches a curve, so the concept of "running the tangents" is to run the shortest distance possible by running straight from one curve to the next.
切线是一条直线，刚好接触到曲线，所以跑切线是从一个弯道跑到另一个最短的距离。
3
The shortest distance between two points is a straightline - unless you happen to be traveling in an airplane.