19世纪末,英国数学游戏大师杜登尼写了一本书《520个趣味数学难题》,其中有这样一道题:16棵树,栽成15行,每行栽4棵,如何栽?乍看此题似乎无解,其实不然.杜登尼给出了一个美丽的解答,如图1所示.原来这16棵树竟然组成了美丽的正五角星(每个角都相等的五角星)图案.正五角星是一个美丽无比的几何图形,它和谐、对称,世界上许多国家的国旗上有正五角星,中华人民共和国国旗上的图案就是由五个正五角星组成的(如图2). At the end of the nineteenth century, the British mathematics game master Dudeng Ni wrote a book “520 interesting mathematical problems”, of which there is such a question: 16 trees, planted 15 lines, 4 lines per plant, how to plant? It seems that there is no solution, but it is not true .Don Denny gave a beautiful solution, as shown in Figure 1. The original 16 trees actually formed a beautiful positive five-pointed star (each corner is equal to the five-pointed star) pattern. The five-pointed star is a beautiful geometric figure, which is harmonious and symmetrical. Many countries in the world have a positive five-pointed star on the national flag. The pattern on the national flag of the People’s Republic of China consists of five five-pointed stars (Figure 2).