Help drawing circles with turtle

[songminguk]

import turtle
from turtle import *

t = turtle.Turtle()
t.hideturtle()
turtle.bgcolor("light green")
t.penup()
t.goto(-100,-80)
t.pendown()

t.color('red','yellow')
t.begin_fill()
for i in range(3):
t.forward(50)
t.left(90)
t.forward(50)
t.left(90)
t.forward(50)
t.left(90)
t.end_fill()
turtle.done()

This is what i got