Mini-Colossal Octoquadri II: U-Bahn
(Published on 20. March 2025, 02:53 by sfushidahardy)
Mini-Colossal Octoquadri II: U-Bahn
Part of a greater collaboration with MaizeGator, in which we are setting pencil puzzle octoquadri hybrids in the "colossal sudoku" format.
Puzzles in our series so far:
Mini-Colossal Octoquadri I: Loop 12 (MaizeGator).
Mini-Colossal Octoquadri II: U-Bahn (sfushidahardy).
Mini-Colossal Octoquadri III: Sukoro (sfushidahardy).
- Octoquadri: Place 8 of the digits 1-9 in the "Octoquadri" grid, so that every digit occurs twice, and there are no repeats in any row, column, or box. Place the remaining digit in the "Leftover" cell.
- U-Bahn: Draw a connected loop network through the centers of some cells in both grids, which may branch or turn, but may not have any dead ends. Clues indicate how many times the corresponding line shapes (i.e. crosses, branches, straight lines, or turns) appear in the corresponding row or column, irrespective of the line shape's rotation.
- Assign the values "1" to turns, "2" to straights, "3" to branches, and "4" to crosses. In the Mini-Bahn grid, every line shape must agree with the digit in its cell (modulo 4). For example, if the Mini-Bahn network visits a cell containing a 7, that cell must be a branch. To clarify, not every digit (cell) of the mini-Bahn must be visited by the network.
- Interaction: Each cell in the Octoquadri grid corresponds to a 3x3 region in the Mega-Bahn grid. Each Mega-Bahn region contains 12 dotted edges. The digit in each Octoquadri cell is the number of dotted edges crossed by the U-Bahn network in the corresponding region.
I hope you enjoy the puzzle!
Solution code: for each row except the last in the Mega-Bahn grid, the number of u-bahn lines leading down from that row
Comments
on 4. August 2025, 01:37 by askaksaksask
Great puzzle! My progress was very slow and deliberate, which i believe was the intention here. A very intricate logic that is very fun to sort, but certainly no 'silver bullet' that led to a rush of progress. Just a classically consistent pencil puzzle! Great fun, never boring, a nice challenge all around. Thank you!!
on 11. June 2025, 17:58 by sfushidahardy
added sukoro link
on 9. May 2025, 16:49 by CutieRainbow
Love this rewarding puzzle!
on 29. April 2025, 18:20 by chalk235
Very hard - but fair!! Thanks.
on 26. March 2025, 16:19 by Christounet
Phew, that was a hard one ! Combining the logic of U-Bahn and border crossings makes things very tricky to process and it is easy to make mistakes. For future solvers, I would advise to use the edge tool to keep track of certain/potential border crossings. Thanks for the nice workout :)
on 20. March 2025, 12:56 by Myxo
Amazing puzzle! Very hard logic throughout, but super rewarding when you find it.
