Note by the author: Factorio is more fun without this mod! Interpose was developed with
AI-assisted coding, as a fun exercise: the code was not written by humans.

You mark where items come in and what must come out; Interpose builds the factory in between.

Place an input port for each ingredient and an output port for the product (set its item; the
count is the wanted rate per minute). Take the Interpose planner from the shortcut bar and drag over
the area: assembling machines, inserters and belts appear as ghosts, at the right ratios, for robots or
you to build. Alt-drag checks a layout that is already built.

What it does

• Works out how many machines each recipe needs (exact ratios, no modules) and how many inserters
  keep them busy, then routes the belts, with undergrounds where they must cross.
• Moves items too: when the outputs are the inputs' items, it just routes belts, with splitter
  balancers for 1-2, 2-4, 4-2 belts and more.
• Explains every refusal with what to change ("the output port is boxed in: leave a free tile next to
  it"), in a window, in the chat and on the map.
• Per-player settings for the machine, belt and inserter tier.

Limits (for now)

Builds on empty ground only; one product per layout; no fluids; recipes with up to 2 ingredients;
areas up to 100 x 100 tiles.

Safety

Runs only inside the game: no network, no files, nothing collected. Deterministic, so it is
multiplayer-safe. Details: docs/SECURITY.md.

Source, feedback, tests

Open source (MIT) at gitlab.com/barrystaes/interpose,
with a command-line version of the same engine. Every release passes a few hundred automated tests,
including headless in-game runs that build the generated layouts and measure their output. Feedback
and bug reports: GitLab issues (there are
templates for both).