This is a Right Face puzzle.
This type has the same woes as International Borders, in that the ideas behind the puzzle are relatively simple but there are a bunch of technicalities that make the description page appear bloated.
Also, I’m starting to think about the 100th puzzle. I can’t guarantee a 100 by 100 grid size similar to what I did for puzzle 50, but it will at least be large and very challenging. However, I haven’t decided what type it should be. If you have any hopes or wishes in this area, you can comment here or email me (palmermebane at gmail dot com).