This code creates a black image of size 500x500 pixels, and then uses the ImageDraw module to draw white squares on it. The squares are 50x50 pixels in size and there are 9 rows and 9 columns of them.

After that, the code uses the transpose() method to create three copies of the original image, each with a different orientation:

img2 is a copy of img that is flipped horizontally (left-to-right).
img3 is a copy of img that is flipped vertically (top-to-bottom).
img4 is a copy of img3 that is flipped horizontally (left-to-right).
Then, the code creates a new image called result that is 1000x1000 pixels in size. It pastes the four copies of the original image (img, img2, img3, and img4) onto this new image, with each copy occupying a quarter of the image.

Finally, the code creates another image called resultfull that is 1100x1100 pixels in size, and pastes result onto it, with a 50-pixel margin on all sides. The final image is then saved to a file called 'ok.jpg'.