The example in Listing 4 creates 10 random quadrilaterals where the points must be in clockwise or counter-clockwise order.
清单4内的示例创建了10个随机的四边形其中这些点必须是顺时针或逆时针顺序。
3
If you find that the line moves slowly and see that another cashier is coming to checkout counter4 to open it for business, you would quickly take your cart to that counter (see Figure 1).