Turtle animation is so fast in python

Question

I made windmill but it is moving so fast. I use turtle library to do that and t2 is only for circle, t makes the main job. I use tracer/update and I tried some numbers inside tracer but nothing changed. How can I do that animation at normal speed?

import turtle
screen = turtle.Screen()
screen.tracer(0)         
t2 = turtle.Turtle()
t2.speed(2)
t2.forward(50)
t2.setheading(90)
t2.circle(50)
t = turtle.Turtle()
t.speed(2)
def rectangle() :
    t.penup()
    t.forward(170)
    t.left(90)
    t.pendown()
    t.forward(5)
    t.left(90)
    t.forward(120)
    t.left(90)
    t.forward(10)
    t.left(90)
    t.forward(120)
    t.left(90)
    t.forward(5)
def windmill():
    for i in range(4):
        rectangle()
        t.penup()
        t.goto(0,0)
        t.pendown()
while True:
    t.clear()
    windmill()
    screen.update()
    t.left(10)

Answer 1

You can use the sleep method from the built-in time module:

import turtle
from time import sleep # Imported here

screen = turtle.Screen()
screen.tracer(0)         
t2 = turtle.Turtle()
t2.forward(50)
t2.setheading(90)
t2.circle(50)
t = turtle.Turtle()
def rectangle() :
    t.penup()
    t.forward(170)
    t.left(90)
    t.pendown()
    t.forward(5)
    t.left(90)
    t.forward(120)
    t.left(90)
    t.forward(10)
    t.left(90)
    t.forward(120)
    t.left(90)
    t.forward(5)
def windmill():
    for i in range(4):
        rectangle()
        t.penup()
        t.goto(0,0)
        t.pendown()
while True:
    sleep(0.05) # Used here
    t.clear()
    windmill()
    screen.update()
    t.left(10)

A smoother way is to just reduce the left amount for each iteration of the while loop:

import turtle

screen = turtle.Screen()
screen.tracer(0)         
t2 = turtle.Turtle()
t2.forward(50)
t2.setheading(90)
t2.circle(50)
t2.speed(2)
t = turtle.Turtle()
t.speed(2)
def rectangle() :
    t.penup()
    t.forward(170)
    t.left(90)
    t.pendown()
    t.forward(5)
    t.left(90)
    t.forward(120)
    t.left(90)
    t.forward(10)
    t.left(90)
    t.forward(120)
    t.left(90)
    t.forward(5)
def windmill():
    for i in range(4):
        rectangle()
        t.penup()
        t.goto(0,0)
        t.pendown()
while True:
    t.clear()
    windmill()
    screen.update()
    t.left(0.2) # Reduced here!