Grandfather Paradox (Yajilin and Reductionism)
(Published on 18. September 2026, 05:03 by Bobuardo da Vinci)
This puzzle is a combination of Yajilin and Reductionism on a fractal grid.
Draw line segments into some cells such that there are no dead ends or branches, and all line segments at all levels are connected.
The left grid exists somewhere inside the right grid shrunk by a factor of three,
and the right grid exists somewhere inside the left grid shrunk by a factor of three
(i.e. each grid occupies a 3x6 rectangle of empty space in the other grid).
In determining the positions of the grids, they may be rotated but not reflected.
Lines may only pass between grids at the given openings around each grid's boundary.
Clues in the left grid are Yajilin clues.
- Shade all cells which remain empty after all line segments have been drawn and the right grid has been placed.
- Shaded cells may not be orthogonally adjacent.
- A numbered arrow indicates how many shaded cells lie in the indicated direction.
- A numbered arrow indicates the number of distinct cell contents in the indicated direction (including empty cells).
- Clue/grey cells and cells which contain the Yajilin grid do not count towards Reductionism clues.
Solve with Penpa interface
Solution code: From top to bottom, the number of empty cells in each row of the reductionism grid. The cells containing the Yajilin grid are not empty. Total length is 18 characters, don't forget the top and bottom rows!
Last changed on on 20. September 2026, 05:48
Solved by Rickium, stefliew, radarvillage, zzw, The Book Wyrm, wisty
Comments
on 29. September 2026, 01:09 by wisty
Wow! I'm speechless! Very long solve, definitely a 5* difficulty imo, but really well put together and such a fascinating challenge! Really enjoyed this, thank you so much
on 20. September 2026, 05:48 by Bobuardo da Vinci
Clarified rules and solution code description.
on 18. September 2026, 05:23 by Bobuardo da Vinci
Fixed mistake in solution code
