SLITHERLINK
The Loop Chronicles — 100 Puzzles · 10 Difficulty Levels
Every Puzzle, Pure Logic
No guessing, no trial and error — every puzzle in this book can be cracked with logical deduction alone. That's a promise most puzzle books can't make.
100 Original Puzzles
Algorithmically generated and rigorously validated. Every puzzle has exactly one solution, proven by a constraint solver — not eyeballed.
10 Difficulty Levels
From beginner-friendly 5×5 grids to demanding 12×12 marathons. Difficulty rises on three axes: grid size, clue density, and reasoning depth.
No Guessing Required
Every puzzle is solvable by propagation and contradiction probing — pure logic, never brute force. Levels 1–3 don't even need probing.
True Difficulty Grading
Difficulty is measured by technique, not clue count. The engine grades by which logical method cracks the puzzle — basic rules, probing, or search.
Monotonic Ladder
No puzzle is easier than any puzzle at a lower level — the build script asserts this automatically. You'll never feel the difficulty regress.
Premium Print Quality
Large-format paperback with clean, readable grids and a full answer key in the back. Designed for pencil solvers, not screens.
10 Levels of Challenge
Difficulty rises on three axes at once: the grid grows, the clues thin out, and the reasoning gets deeper.
| Level | Grid | Clues | Density | Technique |
|---|---|---|---|---|
| 1 | 5 × 5 | 17 | 0.68 | Propagation only — pure beginner |
| 2 | 6 × 6 | 22–23 | 0.61–0.64 | Propagation only |
| 3 | 7 × 7 | 24–30 | 0.49–0.61 | Propagation only |
| 4 | 7 × 7 | 23–29 | 0.47–0.59 | First probing required |
| 5 | 8 × 8 | 31–36 | 0.48–0.56 | Light probing |
| 6 | 9 × 9 | 37–45 | 0.46–0.56 | Moderate probing |
| 7 | 10 × 10 | 44–52 | 0.44–0.52 | Heavy probing |
| 8 | 11 × 11 | 53–58 | 0.44–0.48 | Advanced probing |
| 9 | 12 × 12 | 52–70 | 0.36–0.49 | Deep reasoning |
| 10 | 12 × 12 | 50–66 | 0.35–0.46 | Expert — marathon solving |
Sample Puzzle
A 5×5 Level 1 puzzle — draw a single closed loop along the grid lines so that each number indicates how many of its four edges are used.
Interior Preview
