turtle pitchfork from Python for Kids

import turtle#this will create a large circle and a sm one inside
a = turtle.Pen()
b = turtle.Pen()
c = turtle.Pen()
d = turtle.Pen()

def dt():
    #turtle.write("d1", font=("Arial", 15, "bold"))
    d.forward(50)
    d.left(90)
    d.forward(50)
    d.right(90)
    d.forward(70)
    #d.setpos(x,y)
    d.write('d ', font=("Arial", 15, "bold"))
    #d.write(d.ycor, font=("Arial", 15, "bold"))# error on screen!
    #How to get the text at the END of the line???

def ct():
    c.forward(50)
    c.left(90)
    c.forward(20)
    c.right(90)
    c.forward(50)
    c.write('c', font=("Arial", 15, "bold"))


def bt():
    b.forward(50)
    b.right(90)
    b.forward(20)
    b.left(90)
    b.forward(50)
    b.write('b', font=("Arial", 15, "bold"))

def at():
    a.forward(50)
    a.right(90)
    a.forward(50)
    a.left(90)
    a.forward(70)
    a.write('a', font=("Arial", 15, "bold"))

at()
bt()
ct()
dt()


turtle.exitonclick()# very useful