oriented circle

例句：

1. 1. The oriented circle is a crucial part of the design.
   有向圆环是设计中至关重要的一部分。
2. 2. The oriented circle helps to guide the user's movements.
   有向圆环有助于引导用户的动作。
3. 3.The oriented circle is used to measure the angle between two points on a plane.
   有向圆环用于测量平面上两点之间的夹角。