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The Loop Chronicles — 100 Puzzles · 10 Difficulty Levels
The Loop Chronicles — 100 Puzzles · 10 Difficulty Levels
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.
Algorithmically generated and rigorously validated. Every puzzle has exactly one solution, proven by a constraint solver — not eyeballed.
From beginner-friendly 5×5 grids to demanding 12×12 marathons. Difficulty rises on three axes: grid size, clue density, and reasoning depth.
Every puzzle is solvable by propagation and contradiction probing — pure logic, never brute force. Levels 1–3 don't even need probing.
Difficulty is measured by technique, not clue count. The engine grades by which logical method cracks the puzzle — basic rules, probing, or search.
No puzzle is easier than any puzzle at a lower level — the build script asserts this automatically. You'll never feel the difficulty regress.
Large-format paperback with clean, readable grids and a full answer key in the back. Designed for pencil solvers, not screens.
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 |
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.
