PuzzleForge

Seven great mechanical puzzles, one workshop. Nestor decomposes the tower, Minim finds the fewest moves, Wend searches the states, Gill measures with the GCD, Skiff ferries under the rules, Gray counts in binary to free the rings, Vault reduces the board to one, and Faro looks ahead to clear the jam — and Sprocket shows you how to make your solving strategy visible.

Level 1

For grown-ups — progress report →A private, on-device snapshot mapped to the skill areas practiced. Export a CSV or print — nothing leaves this device.

Solve a puzzle

Seven hands-on puzzles you can actually play, plus a round that asks you to predict the answer before the reveal.

Tower of Hanoi Move the whole tower one disk at a time. Recursion + the fewest-moves rule (2ⁿ−1). Sliding Tiles Slide 1–8 into order. State-space search — and every scramble here is solvable. Water Jugs Measure an exact amount with two unmarked jugs. The GCD decides what’s possible. River Crossing Ferry the wolf, goat, and cabbage across — never leave a forbidden pair alone. Chinese Rings Free the rings from the bar along the binary Gray-code path — one ring at a time. Peg Solitaire Jump and remove pegs until one is left. Reduction: 14 down to 1. Traffic Jam Slide the cars to clear a path so the red car can escape. Look ahead. Predict the Answer Predict the fewest moves, or whether a puzzle can be solved — then see why.

Choose a kit

Each kit is a short round of questions with hints when you need them. Your progress stays on this device.

Kit 1: Tower of Hanoi Basics recursion — solve the smaller tower first (Tower of Hanoi) · grades 4-5 · 25 questions Kit 2: Optimality & Move-Counting optimality — the fewest moves (2^n - 1) and why it is the minimum · grades 4-5 · 25 questions Kit 3: Sliding-Tile Basics & Solvability sliding-tile (15-puzzle) — blank-adjacent moves and when a scramble is solvable · grades 5-6 · 25 questions Kit 4: State-Space & Reachable Positions state-space search — states, moves, and which positions are reachable · grades 5-6 · 25 questions Kit 5: Look-Ahead & Planning (Rush Hour) look-ahead planning — clear a path by thinking several moves ahead (sliding-block / Rush Hour) · grades 5-6 · 25 questions Kit 6: River-Crossing & Constraints constraint satisfaction — never break the rule (wolf-goat-cabbage; missionaries-cannibals) · grades 5-6 · 25 questions Kit 7: Water-Pouring & GCD GCD / number reasoning — measure exact amounts by pouring between two jugs · grades 6-7 · 25 questions Kit 8: Chinese Rings & Binary Counting binary / Gray-code counting — free the rings by changing exactly one at a time · grades 6-7 · 25 questions Kit 9: Peg Solitaire & Reduction reduction / monovariant — jump-and-remove toward a single survivor (peg solitaire) · grades 6-7 · 25 questions Kit 10: Recursion Deep-Dive recursion — self-similarity, base case, and the recursive trace · grades 6-7 · 25 questions Kit 11: Parity Invariants Across Puzzles parity invariants — the mod-2 argument, generalized across puzzles · grades 6-7 · 25 questions Kit 12: Search Strategies (BFS/DFS intuition) search strategies — breadth-first vs depth-first intuition · grades 7-8 · 25 questions Kit 13: Constraint Satisfaction Deep-Dive constraint satisfaction — modeling, pruning illegal states, and constraint propagation · grades 7-8 · 25 questions Kit 14: Optimality Proofs & Lower Bounds optimality proofs — lower bounds and why you cannot do better · grades 7-8 · 25 questions Kit 15: Number Reasoning in Puzzles number reasoning — gcd, modular arithmetic, and binary behind puzzle moves · grades 7-8 · 25 questions Kit 16: Capstone — Cross-Puzzle Synthesis synthesis — mixed review connecting recursion, search, parity, constraints, optimality, gcd, and reduction · grades 7-8 · 25 questions

Play together

Two ways to keep going — a same-device match with friends, or a trail through every kit. On-device only; nothing leaves this device.

Puzzle Duel (pass-and-play) 2–4 players take turns on one device — same questions for everyone, highest first-try score wins. Puzzle Quest — follow the map → A progression trail through every kit. Clear each stop of real practice, then move on.

More ways to practice

All also on the tab bar above — kept here as quick links:

Mixed practice - revisit what you've learned A short round that shuffles questions from the kits you've played, brought back when they're ready to review. Great for making it stick. puzzleforge Sprint — a calm speed round → Once you’ve mastered a few kits, race your OWN best on what you already know. Timer optional, no penalty for a miss.

📚 Books for PuzzleForge

Read the story, print a workbook, or color the cast — free PDFs to read offline or print at home.

Browse all books →

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