Generates fancy colours by abusing the order(lessness) of a set; it's called ass because i didn't expect it to work so well (or at all)

ass.py

from PIL import Image
import random


def thing(val):
    val += (-4, -3, -2, -1, 1, 2, 3, 4)[random.getrandbits(3)]
    if val < 0: return 0
    if val > 255: return 255
    return val


def neighbours(coord, w, h):
    offsets = ((-1, -1), (-1, 0), (-1, 1), (1, -1), (1, 0), (1, 1), (0, -1), (0, 1))
    for xo, yo in offsets:
        nx = coord[0] + xo
        ny = coord[1] + yo
        if nx >= 0 and nx < w and ny >= 0 and ny < h:
            yield nx, ny


w = 720
h = 1280
im = Image.new('RGB', (w, h))
save_frames = False

done = set()
total = w * h
pending = set()
pending.add((0, 0, 0, (0, 0)))

n_iters = 0
frame = 0
while pending:
    if n_iters % 10000 == 0:
        print(len(done), total, frame)
        if save_frames:
            im.save(f'{frame:04d}.bmp')
            frame += 1

    r, g, b, dest = pending.pop()

    r = thing(r)
    g = thing(g)
    b = thing(b)

    im.putpixel(dest, (r, g, b))
    done.add(dest)
    n_iters += 1

    for neighbour in neighbours(dest, w, h):
        if neighbour not in done:
            pending.add((r, g, b, neighbour))

if save_frames:
    im.save(f'{frame:04d}.bmp')
else:
    im.save('ass.png')

Awoo