# File: tcircle.py
# program to plot several circles
#
# Matt Bishop, ECS 36A, Winter 2019
#
import turtle

#
# create a screen and a turtle
#
wn = turtle.Screen()
tortoise = turtle.Turtle()

# first, draw a circle of radius 50
tortoise.penup()
tortoise.hideturtle()
tortoise.goto(-220,0)
tortoise.showturtle()
tortoise.pendown()
tortoise.circle(50)

# now, a half circle of the same radius
# the curve starts where the turtle is
tortoise.penup()
tortoise.hideturtle()
tortoise.goto(-110, 0)
tortoise.showturtle()
tortoise.pendown()
tortoise.circle(50,180)

# a half circle drawn counterclockwise
tortoise.penup()
tortoise.hideturtle()
tortoise.goto(0, 100)
tortoise.showturtle()
tortoise.pendown()
tortoise.circle(50,180)

# now a quarter circle, drawn clockwise
tortoise.penup()
tortoise.hideturtle()
tortoise.goto(110, 0)
tortoise.showturtle()
tortoise.pendown()
tortoise.circle(50,-90)

# a 60 degree arc
tortoise.penup()
tortoise.hideturtle()
tortoise.goto(170, 50)
tortoise.showturtle()
tortoise.pendown()
tortoise.circle(50,-60)

# ok, done with the turtle!
tortoise.hideturtle()

# draw red lower line
tortoise.penup()
tortoise.pencolor("red")
tortoise.goto(-270, 0)
tortoise.pendown()
tortoise.goto(270,0)

# draw red upper line
tortoise.penup()
tortoise.pencolor("red")
tortoise.goto(-270, 100)
tortoise.pendown()
tortoise.goto(270,100)

# draw dashed middle line
tortoise.penup()
tortoise.pencolor("red")
for i in range(0,68):
    tortoise.goto(-270 + i * 8, 50)
    if i % 2 == 0:
        tortoise.pendown()
    tortoise.goto(-270 + (i+1) * 8,50)
    tortoise.penup()

# now we wait for the window to close
wn.mainloop()