原来还能这样拔草！
What is polygon?
In elementary geometry, a polygon (/ˈpɒlɪɡɒn/) is a plane) figure that is bounded by a finite chain of straight line segments closing in a loop to form a closed polygonal chain or circuit. (cited from wikipedia )
In elementary geometry, a polygon (/ˈpɒlɪɡɒn/) is a plane) figure that is bounded by a finite chain of straight line segments closing in a loop to form a closed polygonal chain or circuit. (cited from wikipedia )