Links: the pictures are for those interested but short of the 10K threshold.
interesting how the deleted posts appear as https: and so on, while the undeleted appear as an underlined question title.
https://math.stackexchange.com/questions/3590234/on-matrix-with-det-0 The current version of the question is still open, as I write this. I now think this is a single OP crowdsourcing, well, something. There may or may not be a visible programming contest involved.