import turtle
t = turtle.Turtle()
t.speed(5) # 1:slowest, 3:slow, 5:normal, 10:fast, 0:fastest
t.forward(100)
t.left(90)
t.forward(100)
t.left(90)
t.forward(100)
t.left(90)
t.forward(100)
t.left(90)
t.forward(50)
t.circle(50)
t.left(90)
t.forward(100)