借鉴如下画一颗树的代码，用函数调用的形式，画出一批森林from turtle import Turtle, mainloop def tree(plist, l, a, f): """ plist is list of pens l is length of branch a is half of the angle between 2 branches f is factor by which branch is shortened from level to level.""" if l > 5: # lst = [] for p in plist: p.forward(l)#沿着当前的方向画画Move the turtle forward by the specified distance, in the direction the turtle is headed. q = p.clone()#Create and return a clone of the turtle with same position, heading and turtle properties. p.left(a) #Turn turtle left by angle units q.right(a)# turn turtle right by angle units, nits are by default degrees, but can be set via the degrees() and radians() functions. lst.append(p)#将元素增加到列表的最后 lst.append(q) tree(lst, l*f, a, f)

好的，我理解了你的要求。以下是基于函数调用的森林绘制代码，你可以在调用时传入不同的参数以绘制不同形态的森林：

from turtle import Turtle, mainloop

def tree(plist, l, a, f):
    """ plist is list of pens
    l is length of branch
    a is half of the angle between 2 branches
    f is factor by which branch is shortened
    from level to level."""
    if l > 5:
        lst = []
        for p in plist:
            p.forward(l)
            q = p.clone()
            p.left(a)
            q.right(a)
            lst.append(p)
            lst.append(q)
        tree(lst, l*f, a, f)

def forest(n, m, l, a, f):
    """ n is the number of trees in the forest
    m is the number of levels of each tree
    l is the initial length of the branches
    a is half of the angle between 2 branches
    f is factor by which branch is shortened
    from level to level."""
    for i in range(n):
        t = Turtle()
        t.hideturtle()
        t.speed(0)
        t.left(90)
        t.penup()
        t.goto(-400 + i*200, -200)
        t.pendown()
        plist = [t]
        for j in range(m):
            tree(plist, l, a, f)
            plist = plist[1::2]
        t.penup()

forest(3, 5, 100, 30, 0.7)
mainloop()

在调用 `forest` 函数时，你可以传入不同的参数来控制绘制的森林：

- `n`：森林中树的数量
- `m`：每棵树的层数
- `l`：树枝的初始长度
- `a`：每个交叉点的夹角
- `f`：每一层树枝长度相对于上一层的缩小比例

例如，`forest(3, 5, 100, 30, 0.7)` 会绘制出三棵树，每棵树有五层，初始树枝长度为 100，每个交叉点夹角为 30 度，每一层长度相对于上一层的缩小比例为 0.7。