import turtle

screen_width = 600
screen_height = 600
screen = turtle.Screen()
screen.setup(screen_width,screen_height)
screen.bgcolor('#c0c0c0')
font1 = ("Arial", 8, "normal")

def create_axis():
    a = screen_width//2
    b = screen_height//2
    dx = screen_width//20
    dy = screen_height//20
    axis = turtle.Turtle()
    axis.hideturtle()
    axis.speed(0)
    axis.color('blue','blue')
    axis.pensize(5)
    axis.penup()
    axis.goto(-a+5,0)
    axis.pendown()
    axis.write(str(-a), move=False, align="left",font = font1)
    axis.goto(a,0)
    axis.goto(a-30,0)
    axis.write(str(a), move=False, align="left", font = font1)
    axis.penup()
    axis.goto(0,-b+5)
    axis.pendown()
    axis.write(str(-b), move=False, align="right",font = font1)
    axis.goto(0,-b)
    axis.goto(0,b-15)
    axis.write(str(b), move=False, align="right", font = font1)
    axis.goto(0,b)
    axis.pensize(1)

    for n in range(21):
        x = -a + n*dx
        axis.penup()
        axis.goto(x,-b)
        axis.pendown()
        axis.goto(x,b)
    for n in range(21):
        y = -b + n*dy
        axis.penup()
        axis.goto(-a,y)
        axis.pendown()
        axis.goto(a,y)        

create_axis()
