Log 8 - Making Puzzles

Pico² » Devlog

2025-04-12 by wsasaki01 (@wsasaki01)

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Pico² is releasing soon on PICO-8! Follow on itch.io for updates!

We’re so back!!

It’s been a minute - had lots of work to do and had to pause development. But I’m back into it now, and have spent the last two days thinking about how I’m going to create the puzzles themselves.

I wanted a way to quickly edit and test puzzles without editing raw text. I considered making a separate PICO-8 app for this, but this platform isn’t great for saving data to external sources.

Then I realised: Excel! It’s perfect for grid-based data, can be customised with macros, and I can read .xlsx in Python with a library. I can even then inject this straight into the Lua code, creating a super convenient pipeline that lets me edit puzzles and play them in Pico² within just a few seconds.

Excel to Pico²

The Excel sheet has square cells in the first columns, and conditional formatting to fill in the cell when it has value y. Macros are used to toggle between filled and crossed cells - this editing mode can be toggled with the “on” cell at the top of each sheet.

Excel makes for a very intuitive Picross puzzle editor.

Next, in Python, I load this using openpyxl, reading each line and compiling them into a Puzzle object. This includes all the puzzle solving functions I made previously, so as soon as they’re loaded in I get a report in the terminal about which puzzles are solvable. Nice!

Puzzle 16 in World 2 isn’t solvable!

I’ve also got a text file with the puzzle names. These are all written directly into levels.lua, which is #include’d in the game cart. Best of all, I can use my solver in PICO-8 itself to fill the puzzle as far as possible, highlighting which parts of the grid need changing to make the puzzle solvable.

Pico² reveals which parts of the unsolvable puzzle are causing issues.