I've been meaning to explore wraparound grids with internal/external clues ever since setting this puzzle. I'm very pleased with the result, and hope you will have as much fun solving it as I did setting it. I got a range of feedback regarding difficulty estimation, and 4-star estimate definitely assumes familiarity and comfort with the standard full rank constraint.
On that note, thanks to Manta-Ray, ChinStrap, and kingoffries for testing and rule advice.
Rules:
Sudoku: Place the digits 1-9 once each in every row, column, and box.
Thermometers: Digits along a thermometer strictly increase from the bulb end.
Klein Bottle Grid: The edges of the grid wrap around, such that the left edge wraps to the right. The top and bottom also connect, but have undergone a twist such that the left end of the top wraps to the right end of the bottom. This is reflected in the coloring.
Full Rank, You-can't-escape-the-grid edition: Each row and column represents two nine digit numbers, one when read forwards and the other when read backwards. A value in a pointing pill represents the rank of the nine digit number that begins with the cell on the other side of grid border that the pill points towards. Rank 1 has the smallest value and Rank 36 the largest. There are no tied ranks. Two-cell pills are two digit numbers, read in Western reading order (so the left/top digit is the tens digit, and the right/bottom is the units digit).
Clues outside the grid are duplicates of the clues inside the grid, to help keep track of the twisted grid layout.
Click the puzzle to play!
Lösungscode: Column 3, from top to bottom
am 3. April 2026, 05:14 Uhr von aqjhs
i need topological full rank on tap
am 2. April 2026, 21:40 Uhr von kingoffries
Very clever puzzle. I enjoyed the full rank interactions with the looping grid.
am 2. April 2026, 21:16 Uhr von Manta-Ray
Amazing construction!