[Python] Making multiple turtles in one window

I want to make more than two turtles when I run the modules. So I declared two variables on turtle but there's only one turtle I can see. What's wrong with my code?

import turtle
t1=turtle.Turtle()
t2=turtle.Turtle()

colors = ["red", "blue", "green"]
turtle.bgcolor("yellow")
t1.speed(3)
t1.width(5)
length1 = 10
t2.speed(3)
t2.width(5)
length2 = 10

while length1 < 500:
t1.fd(length1)
t1.pencolor(colors[length1%3])
t1.right (89)
length1 += 3 #length1 = length1 + 3

while length2 < 500:
t2.fd(length2)
t2.pencolor(pink)
t2.left (89)
length2 += 4 #length2 = length2 + 4

input()

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