One rule, three sizes, infinite puzzles.
Click any cell to flip it and its four orthogonal neighbors. Goal: turn every light off. Pick from 3×3, 5×5, or 7×7 — each generated solvable from an all-off seed by a guaranteed-solvable random toggle sequence.
Stuck? The Hint button runs a Gauss-Jordan elimination over GF(2) on the toggle-incidence matrix to find the optimal click set, then pulses one of those cells. Best-moves are saved per grid size in localStorage.
⚙️ Settings & Customization
- Theme
- Language
- Size
- Transparent background
- 🎨 Accent Color
📖 How to embed in Notion
- Copy the embed link from the sidebar on the right.
- Open the Notion page you want the widget on and type
/embed. - Paste the link into the embed dialog and press
Embed link. - Drag the embed's bottom edge to resize it to taste.
🆕 What's new in v1.1
- ✦ 21 languages with RTL for Arabic & Hebrew
- ✦ Three grid sizes — 3×3, 5×5, 7×7
- ✦ GF(2) Gauss-Jordan solver powers the hint
- ✦ Best-moves tracked per grid in localStorage
- ✦ Keyboard shortcuts — H for hint, N for new puzzle
- ✦ Solvable-from-all-off generation guarantees no dead boards
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