#import Python turtle module
#More info see https://docs.python.org/2/library/turtle.html
import turtle
base = 1 #set the length for base case
reduction = 6 #length decreased
def drawSpiral(myTurtle, lineLen):
if lineLen <= base: # base case
myTurtle.forward(base)
else:
#Move the turtle forward by lineLen in the direction the turtle is headed.
myTurtle.forward(lineLen)
#Turn turtle right by 90 degrees.
myTurtle.right(90)
#Recursively do this by decreasing the lineLen
drawSpiral(myTurtle,lineLen - reduction)
##Initialize the turtle
t = turtle.Turtle()
myWin = turtle.Screen()
t.speed(6) #Set the turtle's speed. 1 is slow and 10 is fast.
t.color("blue") #Set the turtle's color.
t.pensize(2) #Set the pen size
##Set the value for size
size = 200
t.up() #Pull the pen up - no drawing when moving.
t.setposition(-size/2,size/2) #move the turtle to the starting point
t.down() #Pull the pen down - drawing when moving.
##draw the spiral
drawSpiral(t,size)
##exit the drawing screen
myWin.exitonclick()
Program Revised from http://interactivepython.org/runestone/static/pythonds/Recursion/pythondsintro-VisualizingRecursion.html
