Nim & Friends
An interactive puzzle app where students play classic combinatorial games like Nim, Hackenbush, Wythoff, and Chomp against an AI opponent that explains the winning strategy in plain language after each move.
High school and university students learning game theory, math olympiad participants, and puzzle hobbyists
- Eight-plus combinatorial games with adjustable difficulty from beginner to olympiad-level
- Post-game strategy revealer that shows the 'cold' positions and the math behind the AI's moves
- Bite-size lessons on Sprague-Grundy theory, nimbers, and surreal numbers with diagrams
- Sandbox: design your own impartial game and let the AI find its Grundy value
Formal combinatorial game theory is advancing fast in research tools like Lean 4, but the consumer learning side is still stuck on clickbust puzzle apps, and students want a serious way to learn the math by actually playing.
Nim apps exist on Play Store/App Store and NRICH hosts Nim as a math problem, but download presence is sparse; the cited HN 'Combinatorial Games in Lean' trend post had only 16 points and 2 comments — a weak demand signal.Nim mathematical strategy game - Apps on Google Play ↗NIM (Impossible difficulty) - Apps on Google Play ↗
No consumer app found that bundles Nim + Hackenbush + Wythoff + Chomp with a play-and-explain-AI loop; the closest (MathAtlas) is a static web reference, and Brilliant treats game theory as one topic among thousands.MathAtlas - Interactive Math Learning ↗Brilliant Premium | Brilliant ↗
Most Nim apps are ad-free and free (no IAP), suggesting low willingness to pay for narrow CGT apps; Brilliant proves $24.99/mo or $119.99/yr works for broad STEM, but CGT is a sub-niche where premium pricing will be hard to sustain.Nim mathematical strategy game - Apps on Google Play ↗How much does Brilliant Premium cost? ↗
CGT is a mature but actively researched field (Lean 4 formalization noted in the source trend), and math olympiad prep tools (Gonit, AoPS) sustain long-term demand — the category itself is durable even if the niche is small.Gonit - Best Math Olympiad App ↗Art of Problem Solving ↗
Nim (XOR) and Wythoff (Beatty sequences) AIs are well-documented and straightforward; Chomp's optimal play is open, complicating the 'explain strategy' promise, but overall scope is multi-week, not multi-month engineering.Combinatorial game theory - Wikipedia ↗Combinatorial Games (Erik Demaine) ↗