python 3.x - In a while loop changeing "<" to "<= " in the same code draws a different turtle graphic -

question using while loops.

i notice if use "<" condition in while loop draw different picture if use "<=" condition same code.

below see 2 different code sets , associated pictures render reference.

any or feed appreciated!

for given code use while loop start draw circle squares:

import turtle  def draw_square(some_turtle): count =0 while count <4 :      some_turtle.forward(100)     some_turtle.right(90)     count += 1  def draw_circle():      win = turtle.screen()     win.bgcolor("red")     nic = turtle.turtle()     nic.shape("turtle")     nic.color("blue")     nic.speed(2)     count = 0     while count <4:     draw_square(nic)     nic.right(10)     count += 1      win.exitonclick()  draw_circle() draw_square("1") 

it renders following image:

turtle drawing

i change < <= such:

import turtle

def draw_square(some_turtle): count =0 while count <=4 :      some_turtle.forward(100)     some_turtle.right(90)     count += 1  def draw_circle():      win = turtle.screen()     win.bgcolor("red")     nic = turtle.turtle()     nic.shape("turtle")     nic.color("blue")     nic.speed(2)     count = 0     while count <=4:     draw_square(nic)     nic.right(10)     count += 1      win.exitonclick()  draw_circle() draw_square("1") 

and following rendered:

turtle drawing 2

why changing <= < in while loop have such impact on drawing?

it has position of turtle after square has been drawn. difference in draw_square function.

for first example:

while count <4 :      some_turtle.forward(100)     some_turtle.right(90)     count += 1 

the turtle stops in upper left hand corner of square so:

turtle answer1

if second example change "<" "<=" turtle stops in upper right hand corner because it's including forth loop such:

turtle_answer2

this in-turn changes point in turtle pivots make next square fundamentally changing picture whole.