砂嵐（iOS Pythonista3） https://youtu.be/IRO1EqQQucA

sandstorm.py

from scene import *
from PIL import Image
from random import randrange

MAX_IMG_CNT = 16

class MyScene (Scene):
    def setup(self):
        scale = get_screen_scale()
        self.screen_size = Size(self.size.w * scale, self.size.h * scale)
        img_size = (int(self.size.w / 2), int(self.size.h / 2))
        self.imgs = []
        for i in range(MAX_IMG_CNT):
            img = Image.new('L', img_size)
            pix = img.load()
            for y in range(img.height):
                for x in range(img.width):
                    pix[x, y] = randrange(256)
            self.imgs.append(img)
        self.cnt = 0

    def draw(self):
        name = load_pil_image(self.imgs[self.cnt])
        image(name, 0, 0, self.screen_size.w, self.screen_size.h)
        unload_image(name)
        next_cnt = randrange(MAX_IMG_CNT)
        while self.cnt == next_cnt:
            next_cnt = randrange(MAX_IMG_CNT)
        self.cnt = next_cnt

if __name__ == '__main__':
    run(MyScene(), LANDSCAPE)