Neverending jigsaw puzzle
Just repeat the 6 x 6 bordered stitches change the color of the horizontal jigsaw part after 3 rows and you get a neverending jigsaw puzzle. I think a blanket would look great with it.
Could als turn into a pair of cool socks …
If you use black or white for the not colour changing puzzle part you will be more flexible with the colour of the other puzzle part. So I recommend you use either black or white (I prefer offwhite) for the not changing puzzle part.