Animation of Sierpinski Triangle Tree with Turtle (Source Code)

Animate the transition from Sierpinski Triangle tree to Fractal tree as shown. This project is related to Sierpinski Triangle and Fractal Tree.

Source Code:

import turtle
turtle.title('Sierpinski Tree Animation - PythonTurtle.Academy')
turtle.setworldcoordinates(-2000,-2000,2000,2000)
screen = turtle.Screen()
screen.tracer(0,0)
turtle.speed(0)
turtle.hideturtle()

def sierpinski_tree(x,y,length,tilt,angle,n):
    if n==0: return
    turtle.up()
    turtle.goto(x,y)
    turtle.seth(tilt)
    turtle.down()
    turtle.fd(length)
    sierpinski_tree(turtle.xcor(),turtle.ycor(),length/2,turtle.heading(),angle,n-1)
    
    turtle.up()
    turtle.goto(x,y)
    turtle.seth(tilt+angle)
    turtle.down()
    turtle.fd(length)
    sierpinski_tree(turtle.xcor(),turtle.ycor(),length/2,turtle.heading(),angle,n-1)

    turtle.up()
    turtle.goto(x,y)
    turtle.seth(tilt-angle)
    turtle.down()
    turtle.fd(length)
    sierpinski_tree(turtle.xcor(),turtle.ycor(),length/2,turtle.heading(),angle,n-1)

def animate():
    global angle
    turtle.clear()
    sierpinski_tree(0,-250,1000,90,angle,7)
    screen.update()
    angle = 120 if angle <= 20 else angle-2
    screen.ontimer(animate,50)

angle = 120
animate()
screen.mainloop()