# tk_no_rnd_import.py

# tk_no_rnd_import.py
import tkinter as tk

width, height = 400, 400
grid_size = 40
cell_width = width // grid_size
cell_height = height // grid_size
colors = ["red", "green", "blue", "yellow", "purple", "orange"]
L = len(colors)

colors_cache = [['grey' for _ in range(grid_size)] for _ in range(grid_size)]

root = tk.Tk()
root.title("# tk_rand_vs_perm.py")
canvas = tk.Canvas(root, width=width, height=height)
canvas.pack()

def draw_grid(i,j):
    x0 = i * cell_width
    y0 = j * cell_height
    x1 = x0 + cell_width
    y1 = y0 + cell_height
    canvas.create_rectangle(x0, y0, x1, y1, fill=colors_cache[i][j], outline="")

def permute_colors():
    canvas.delete("all")
    flat = sum(colors_cache, [])
    flat = flat[2:] + flat[:2]  # Rotate colors
    for i in range(grid_size):
        flat = flat[i:] + flat[:i]  # Rotate colors
        for j in range(grid_size):
            colors_cache[i][j] = flat[i * grid_size + j]
            draw_grid(i,j)

def set_colors():
    canvas.delete("all")
    n = 0
    for i in range(grid_size):
        for j in range(grid_size):
            colors_cache[i][j] = colors[n % L]
            draw_grid(i,j)
            n += 1

set_colors()

while 1:
    permute_colors()
    root.update()