draw a trumpet

#程序练习题2.8
from turtle import *
setup(650,350,200,200)
penup()
fd(-100)
seth(90)
fd(100)
pendown()
pensize(1)
pencolor((0,0,0))
i=1
while(i<=100):
    seth(90)
    fd(i)
    seth(180)
    fd(i+1)
    seth(270)
    fd(i+2)
    seth(0)
    fd(i+3)
    i+=1