用循环，并用*****打出一个棱形

   *   
  ***  
 ***** 
*******
 ***** 
  ***  
   *   

代码实现：

size = 4  # 棱形大小
for i in range(size):
    for j in range(size - i):
        print(" ", end="")
    for j in range(2 * i + 1):
        print("*", end="")
    print()
for i in range(size - 2, -1, -1):
    for j in range(size - i):
        print(" ", end="")
    for j in range(2 * i + 1):
        print("*", end="")
    print()

输出结果：

   *   
  ***  
 ***** 
*******
 ***** 
  ***  
   *