The Jupyter Notebook cell keeps being run (never stops)

Question

In my coursework, I have to create the following picture (with one piece with no effect on it)

Below is what I have tried so far:

import PIL
from PIL import Image
from PIL import ImageEnhance
from PIL import ImageDraw
from PIL import ImageFont

fnt = ImageFont.truetype('readonly/fanwood-webfont.ttf', 75)
# read image and convert to RGB
image=Image.open("readonly/msi_recruitment.gif").convert('RGB')
drawing_object = ImageDraw.Draw(image)

# build a list of 9 images which have different brightnesses
enhancer=ImageEnhance.Brightness(image)
images=[]
x = 0
for i in range(0, 10):
    x += 1
    z = x 
    if x % 3 == 0 :
        z = 9
        drawing_object.rectangle((0,450,800,325), fill='black')
        drawing_object.text((20,350),'channel intensity 0.{}'.format(z), font=fnt, fill=(255,255,255))

    elif x % 3 == 1: 
        z = 1
        drawing_object.rectangle((0,450,800,325), fill='black')
        drawing_object.text((20,350),'channel intensity 0.{}'.format(z), font=fnt, fill=(255,255,255))

    else:
        z = 5
        drawing_object.rectangle((0,450,800,325), fill='black')
        drawing_object.text((20,350),'channel intensity 0.{}'.format(z), font=fnt, fill=(255,255,255))
    images.append(enhancer.enhance(10/10))

## create a contact sheet from different brightnesses
first_image=images[0]
contact_sheet=PIL.Image.new(first_image.mode, (first_image.width*3,first_image.height*3))
x=0
y=0

for img in images:
    # Lets paste the current image into the contact sheet
    
    contact_sheet.paste(img, (x, y) )
    
    #-->> I think the problem starts HERE <<--
    pixels = img.load()
    w = image.width
    h = image.height

    for x in range(3 * w):
        for y in range(3 * h):

            #-------0th row---------

            if x in range(0, w) and y in range(0, h): # grid[0,0]
                for i in range(w):
                    for j in range(h):
                        pixels[i, j] = (0,0,90)

            elif x in range(w, 2 * w) and y in range(0, h): # grid[0,1]
                for i in range(w):
                    for j in range(h):
                        pixels[i, j] = (0,0,50)

            elif x in range(2 * w, 3 * w) and y in range(0, h): # grid[0,2]
                for i in range(w):
                    for j in range(h):
                        pixels[i, j] = (0,0,10)

            #--------1st row---------


            elif x in range(0, w) and y in range(h, 2 * h): # grid[1,0]
                for i in range(w):
                    for j in range(h):
                        pixels[i, j] = (90,0,0)

            elif x in range(w, 2 * w) and y in range(h, 2 * h): # grid[1,1]
                for i in range(w):
                    for j in range(h):
                        pixels[i, j] = (50,0,90)

            elif x in range(2 * w, 3 * w) and y in range(h, 2 * h): # grid[1,2]
                for i in range(w):
                    for j in range(h):
                        pixels[i, j] = (10,0,0)

            #--------2nd row----------

            elif x in range(0, w) and y in range(2 * h, 3 * h): # grid[2,0]
                for i in range(w):
                    for j in range(h):
                        pixels[i, j] = (0,90,0)

            elif x in range(w, 2 * w) and y in range(2 * h, 3 * h): # grid[2,1]
                for i in range(w):
                    for j in range(h):
                        pixels[i, j] = (0,50,0)

            elif x in range(2 * w, 3 * w) and y in range(2 * h, 3 * h): # grid[2,2]
                for i in range(w):
                    for j in range(h):        
                        pixels[i, j] = (0,10,0)
    
    # Now we update our X position. If it is going to be the width of the image, then we set it to 0
    # and update Y as well to point to the next "line" of the contact sheet.
    if x+first_image.width == contact_sheet.width:
        x=0
        y=y+first_image.height
    else:
        x=x+first_image.width



# resize and display the contact sheet
contact_sheet = contact_sheet.resize((int(contact_sheet.width/2),int(contact_sheet.height/2) ))


        
display(contact_sheet)

Here the image is the piece I am given. When I run this the Jupyter Notebook cell keeps being run [*]. Well, before I added the part of the code with pixels (after #-->> I think the problem starts HERE <<--) I had this grid exactly in the same view but without color effects. But now, I probably made some mistakes.

Answer 1

In the following part of the code -

            elif x in range(w, 2 * w) and y in range(2 * h, 3 * h): # grid[2,1]
                for i in range(w):
                    for j in range(h):
                        pixels[i, j] = (0,50,0)

            elif x in range(2 * w, 3 * w) and y in range(2 * h, 3 * h): # grid[2,2]
                for i in range(w):
                    for j in range(h):        
                        pixels[i, j] = (0,10,0)

... Aren't you just updating the whole range(w) and range(h) with values again and again? Is that what you want? You are checking if x and y are in a certain range, but then you are just writing each pixel with some value, instead of writing specific pixels.