废话不多说，直接上代码

黑白版

import turtle

turtle.speed(0)
for i in range(500):
    turtle.fd(i)
    turtle.right(91)

turtle.mainloop()

彩色版

import turtle
t = turtle.Pen()
turtle.bgcolor("black")

sides=4
colors=["red","yellow","green","blue",]
for x in range(500):
    t.pensize(1)
    t.speed(0)
    t.pencolor(colors[x%sides])
    t.forward(x*1/sides+x)
    t.left(360/sides+1)
    t.width(x*sides/1)