Lights Out in Python

Presses

Still lit

Best

—

⌨️ Controls

← → ↑ ↓ move the dashed cursor
Space or Enter press the square
Clicking or tapping a square works too
P pause • R new puzzle
🎮 Xbox controller? Just plug it in or pair it — the stick and D-pad are the arrow keys, A is SPACE, Menu pauses and View starts again

🎯 How to play

Pressing a square flips it and its four neighbours — a plus shape.
At the edges the cross is smaller, because some neighbours do not exist.
Turn every light off to win.
Every puzzle can be solved — the game builds them by pressing, so they can always be un-pressed.

💡 Two tricks

Pressing the same square twice puts everything back. Every move is its own undo.
So the order you press in does not matter at all — only which squares you press.
That means every puzzle has a shortest answer, and no square ever needs pressing twice.
Try solving the top row first, then work down. It really helps.

🧑‍💻 This whole game is Python

There is almost no JavaScript on this page. The browser downloaded Pyodide — a complete Python interpreter compiled to WebAssembly — and then ran the .py files in funtime/pylib/. Python does the rules, the maths and the drawing.

File	What it does	Good functions to try re-writing
pylib/lights_rules.py	The rules: the cross, the flips, the win	`light_index`, `neighbours`, `press_light`, `create_puzzle`
pylib/lights_draw.py	Painting the lights — Python calling the canvas	`draw_light`, `square_at_pixel`, `render_game`
pylib/lights_web.py	The glue: clicks, keyboard, the scoreboard	`do_action`, `on_board_click`, `start_game`

🔍 Compare the two versions. Open lib/lights-rules.js and pylib/lights_rules.py side by side — same ideas, two languages.

🛠️ Build it yourself: Build Lights Out in Python walks you through the functions one at a time.

⚠️ If the game never starts: the page has to read its .py files, which a browser will not do for a page opened straight off your disk. Use the live site, or run python3 -m http.server in the project folder.