Since this was just linked from the PR 2020 discussion: https://logicmastersindia.com/forum/forums/thread-view.asp?tid=2737#...

Just want to note one downside of this suggestion, compared to the version used on PR (which was to ask for a sequence of N numbers 0/1/2 counting the "horizontal" bridges in a row of N+1 clues). Namely, that the suggestion here has no fixed length. Some form of checksum like a fixed length or sum is very useful to avoid typos.