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pythonpython-3.xdrawturtle-graphics

Using loops to to draw patterns with turtle module

I am trying to draw this pattern using the turtle module:

enter image description here

Not only this one, but I am also having trouble when applying loops to draw any kind of patterns (especially when it comes to patterns with different shapes lying inside each other, I just simply do not know where to start and how to organize the functions to draw those kinds of complex patterns like that). Therefore, I usually go step by step knowing that there should be a loop to make the turtle do the same thing all over again.

Here is what I have so far:

import turtle
wn = turtle.Screen()
t = turtle.Turtle()

def pattern(t,clr):
    t.screen.bgcolor("white")
    t.pensize(10)
    for i in range(2):
        t.pd()
        t.fd(100) ##
        t.rt(90)
        t.fd(100) ##
        t.rt(90)
        t.fd(90)  ##
        t.rt(90)
        t.fd(75)  ##
        t.rt(90)
        t.fd(70)  ##
        t.rt(90)
        t.fd(38)  ##
        t.rt(90)
        t.fd(38)  ##
        t.pu()
        t.lt(90)
        t.fd(77)
        t.pd()
        t.lt(90)
        t.fd(38)
        t.rt(90)
        t.fd(38)
        t.rt(90)
        t.fd(70)
        t.rt(90)
        t.fd(75)
        t.rt(90)
        t.fd(90)
        t.rt(90)
        t.fd(100)
        t.rt(90)
        t.fd(100)
pattern(t,"black")

enter image description here

Any tips and advices would be much appreciated!

Solution

  • Looking at the original image, and your program's output, you seem to focus on black lines on a white background, not noticing that this can be seen as white lines on a black background. That is, the width of pen strokes matches the width of the gaps between strokes. Let's start by simply overlaying a grid on the image:

    enter image description here

    Now we can describe the image in terms of grid blocks, using a grid block of arbitrary size. Here's your program rewritten in terms of grid blocks:

    from turtle import Screen, Turtle

BLOCK = 15

def pattern(turtle):
    turtle.pensize(BLOCK)

    for _ in range(2):
        turtle.pd()
        turtle.fd(BLOCK * 6)
        turtle.rt(90)
        turtle.fd(BLOCK * 6)
        turtle.rt(90)
        turtle.fd(BLOCK * 5)
        turtle.rt(90)
        turtle.fd(BLOCK * 4)
        turtle.rt(90)
        turtle.fd(BLOCK * 3)
        turtle.rt(90)
        turtle.fd(BLOCK * 2)
        turtle.rt(90)
        turtle.fd(BLOCK * 1)
        turtle.pu()
        turtle.lt(90)
        turtle.fd(BLOCK * 4)
        turtle.lt(90)
        turtle.pd()
        turtle.fd(BLOCK * 1)
        turtle.rt(90)
        turtle.fd(BLOCK * 2)
        turtle.rt(90)
        turtle.fd(BLOCK * 3)
        turtle.rt(90)
        turtle.fd(BLOCK * 4)
        turtle.rt(90)
        turtle.fd(BLOCK * 5)
        turtle.rt(90)
        turtle.fd(BLOCK * 6)
        turtle.rt(90)
        turtle.fd(BLOCK * 6)

turtle = Turtle()

pattern(turtle)

screen = Screen()
screen.exitonclick()

    enter image description here

    Looking at this modified code and image, do you get a sense of where you might be able to consolidate code by using a loop?