This is the third installment of the Fortnightly Topic Challenges Rerun described here and the forty-fourth installment of the FTCs overall, with topics suggested and voted on here. This fortnight's topic is "Introduce a new grid deduction genre to the community" (suggested by Bubbler) and will span from the 29th of November to the 12th of December. During this period, we will compile the list of relevant questions and post it as an answer to this question.

In the meantime, please go and propose and vote on future challenges!

Everyone have fun, and happy puzzling!

Link to other Fortnightly Topic Challenges.

The suggestion is copied to this post for posterity.

Introduce a new grid deduction genre to the community

We already had two Fortnights related to : vanilla one as #24, and hybrids as #32. So this one will be the threrun in this topic. Then you ask, "Why the third time?"

I enjoy grid deduction a lot, but the same genre posted over and over builds up a "genre fatigue". Recently I introduced two new types of grid deduction puzzles:

  • Trichain, which I made up from scratch, and
  • Heteromino, which I found by randomly browsing the Internet (googling the title gives very few results).

There must be a reason to the fact that the two "introduction" puzzles are among the top 3 of all of my puzzles, and repeated posts of the same genre earn fewer and fewer upvotes, even though the quality gets better (at least IMO).

Therefore, the challenge is as the title says: Introduce a new grid deduction genre to the community!


  • The genre must be unseen on Puzzling before the start of the Fortnight.
  • Only one puzzle per user per genre qualifies. (This is to account for the possibility of multiple users working on the same new genre.)
  • For mashups of multiple genres, at least one of the genres must satisfy the above. An existing genre with extra rule(s) or mashups of existing genres do not qualify.

1 Answer 1


List of all questions published as part of the Fortnightly Topic Challenge #44:

The highest-voted three of these are:

The most viewed three of these are:

  • $\begingroup$ Wow, this really was athin's dream fortnight - 5 entries! (descending whistle) $\endgroup$
    – Stiv
    Dec 16, 2020 at 10:46

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