Guide
You run one factory's production line, racing two AI-run rivals for the same customers over 100 days. Buy raw materials, add or sell machines, borrow from the bank — and keep finished goods on the shelf when customers come, or they'll buy from someone else. The whole game is Little's Law made playable: the last section spells out exactly how.
Starting a game
Every company starts identical: 5 machines, $20,000 in cash, no debt, and a 33.3% share of the market. Leave the seed blank for a fresh game, or enter one to replay exactly the same days — same demand, same rivals — and see whether a different plan does better.
Reading the board
Material flows left to right: from the material suppliers, through each company's line, to the customers. Your line is outlined in green; the two rivals sit above it. Each line has three columns:
- Raw materials
- What you've bought and haven't started on yet. The one place a backlog builds before production: buy faster than your machines can work and it piles up here, tying up cash.
- Processing
- How many units your machines worked on today — never more than your capacity, and never more than the raw materials on hand to feed them.
- Finished goods
- Units ready to sell. Customers buy from here; if it runs dry before they're satisfied, you've failed that day's demand.
Beside each line: machines and capacity, cycle time, and — for your line only — cash and debt. The bar along the bottom shows the unit economics, everyone's sales today, and how far through the 100 days you are.
Daily purchase
Your main lever. Set how many units of raw material to buy each day, then press Set daily purchase — the slider alone doesn't save it. Each unit costs $35.00 and sells as a finished good for $45.00. You only ever buy what you can afford that day. Everything after the purchase is automatic: machines pull from raw materials, and whatever they process becomes finished goods the same day.
Machines
Each machine processes 1 unit a day, so machines set your capacity. A new machine costs $10,000; selling one returns only $5,000. Buying capacity you don't need and selling capacity you'll want back are both expensive mistakes.
The Bank
Borrow and repay in steps of $5,000. Your credit line is 70% of your machines' value — $35,000 with the starting 5 machines — and it grows or shrinks as you buy or sell them. Interest is 10% a year, charged daily in cash. If you can't pay it, the bank sells your machines at the resale price until the interest is covered — losing far more capacity than the interest was worth.
Demand and market share
Total demand grows over the game, from 12 units a day at the start to 24 by the end, and swings up to 25% either way on any given day. Each company's customers are its market share of that total.
Fail to fill your customers' demand on a day and you lose 0.5 points of market share to whichever rivals did fill theirs. On a day when everyone falls short — or no one does — nothing moves. Lost share only comes back the same way: on a day a rival falls short and you don't.
Your competitors
Each rival runs on its own habits, set at the start of the game: some buy lean, just enough for today's demand, others keep a buffer; some add machines readily, others hesitate; some lean on the bank sooner than others. You can see their lines and market share, but not their cash or debt — read their habits from how their columns move.
Advancing the day
Advance 1 Day runs everyone's day in order: the rivals make their decisions, every line buys and processes, the bank collects interest, customers buy, and market share moves. Your controls act immediately, so make your changes before you advance.
Game over
After day 100 the company with the most final equity wins: cash plus machines at full price, minus debt. The debrief ranks all three by it and shows their final market share alongside — share keeps your customers coming, but it isn't the score. Your Stats page counts a win the same way. Replay the seed to try a different plan against the very same days.
Little's Law, in this game
Little's Law says that for any process, work in progress = throughput × cycle time. Here:
- Throughput
- → Units your machines complete a day — capped by capacity (machines × 1).
- Work in progress
- → The Processing column: what the machines are working on today.
- Cycle time
- → Never set directly — it's processing ÷ throughput, shown beside each line.
Push more material in than the line can process and the extra doesn't come out faster — it waits, in raw materials, costing cash. Starve the line and throughput falls, finished goods run dry, and customers leave. The game is finding the flow your capacity can actually sustain as demand grows, and adding capacity before you need it, not after.