Rules:
Pento loop: Place all the twelve pentominos in the grid exactly once (including rotations and reflections), creating a closed ring. Every pentomino must be connected to exactly two different other pentominos in the ring. Two connected pentominos can only touch in a single edge.
The pentomino ring divides the grid into three different regions made of orthogonally connected cells: the ring region, the central region and the outer region.
Numbers in the grid have different meanings depending on where they are:
Solution code: Row 5, from left to right (14 letters): put the letter O for a cell in the outer region, the letter R for a cell in the ring region and the letter C for a cell in the central region. Es: OOORCCRCRROOOR
on 5. February 2026, 00:28 by zzw
Awesome puzzle, loved it! Really cool ruleset (seeing some Richard influence here too haha). Definitely makes the most of the interactions between the rules, right from the tough but very
interesting breakin.
on 15. November 2025, 17:41 by yttrio
Very cool ruleset, and a great entry for the round!
on 15. November 2025, 17:03 by Christounet
Excellent puzzle, with an original ruleset that leads to very unique deductions. Some deductions require a visualisation of the connectivity that is quite hard but fair. One of my prefered of this round. Thanks :)
on 15. November 2025, 13:51 by Agent
A one-of-a-kind puzzle, ery challenging and with some very distinctive deductions!
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