Results 2 issues of 包打听

I need to create a concave polygon. Some tutorials mention b2Separator, but I haven't found it in this item. Do I need to write one b2Separator?

RT. ![QQ截图20210108171235](https://user-images.githubusercontent.com/2215019/103996479-ddbd0100-51d4-11eb-85cd-b0b72a2905a8.jpg) ![QQ截图20210108171335](https://user-images.githubusercontent.com/2215019/103996485-e01f5b00-51d4-11eb-9ae0-3967064e2500.jpg)