Python Turtle draws fractal tree recursively

Recursive function draws fractal tree

The basic idea of ​​fractal geometry: objective things have a hierarchical structure of self-similarity, and the parts and the whole have statistical similarity in form, function, information, time, space, etc., called self-similarity, self-similarity is Refers to the property that the local is a proportional reduction of the whole.

code show as below:



## 绘制分型树,末梢的树枝的颜色不同

import turtle

def draw_brach(brach_length):

    if brach_length > 5:
        if brach_length < 40:
            turtle.color('green')

        else:
            turtle.color('red')

        # 绘制右侧的树枝
        turtle.forward(brach_length)
        print('向前',brach_length)
        turtle.right(25)
        print('右转20')
        draw_brach(brach_length-15)
        # 绘制左侧的树枝
        turtle.left(50)
        print('左转40')
        draw_brach(brach_length-15)

        if brach_length < 40:
            turtle.color('green')

        else:
            turtle.color('red')

        # 返回之前的树枝上
        turtle.right(25)
        print('右转20')
        turtle.backward(brach_length)
        print('返回',brach_length)

def main():
    turtle.left(90)
    turtle.penup()
    turtle.backward(150)
    turtle.pendown()
    turtle.color('red')

    draw_brach(100)

    turtle.exitonclick()

if __name__ == '__main__':
    main()