New here? What this game is, the idea behind it, the rules, and what the app can do.
No class running? Play a full chain by yourself — you pick one link, robots play the other three. Same rules as the classroom game.
Choose your link and the game setup. The other three links are played by robots. The game starts immediately.
In class? Join the session your facilitator is running. You'll pick a link in the chain and see only your own shelf.
Enter the code your facilitator is showing and your name — or scan the projected QR with your camera.
Facilitators: set up a session, then project the code (and QR) for students to join from their phones.
Set up a session, then show the code (and QR) for students to join from their phones. Empty seats are played by the computer.
A halal re-theming of the MIT Beer Distribution Game · runs on your own server.
A multiplayer, phone-based re-theming of the MIT Beer Distribution Game (Forrester's production–distribution game, popularised by Sterman). Beer becomes dates (التمر), and the demand shock becomes the Ramadan surge: families buy dates for every iftar, so retail demand climbs through the fasting weeks and peaks at Eid.
Each team is a serial four-echelon supply chain — grocer, wholesaler, distributor, date farm. Every player manages one echelon with local information only: their own inventory, backlog, and the orders arriving from their immediate customer. Orders travel upstream and shipments downstream with fixed lead times (default: 2-week order delay + 2-week shipping delay). The single weekly decision per echelon is the order quantity. Unfilled demand backlogs — it is never lost.
Costs accrue weekly: holding 0.5 AED per box in stock, backlog 1.0 AED per box owed — the classic 1:2 ratio. Team score is total chain cost; lowest wins. The system starts in steady state at 4 boxes/week: if everyone simply ordered 4, nothing would move.
The bullwhip effect: demand-variance amplification as you move upstream. A modest, calendar-predictable seasonal surge at the grocer becomes a flood of orders at the farm — typically several times the customer's variance. The drivers are the ones from the literature: order/shipping delays, local-only information, and behavioural under-weighting of the supply line (players anchor on inventory and forget what they already ordered). The sharper-than-beer teaching point: Ramadan is on the calendar every year and the whip still happens — predictability alone doesn't fix it; demand sharing and shorter lead times do.
Ramadan surge (default): flat 4/week, then a ramp to a 3× Eid peak followed by a post-Eid lull. Everyday: constant 4/week — pure behavioural bullwhip, no shock at all. Weddings & Eids: stochastic spikes for a noisier season.
Free and open source. Used in a university operations & supply-chain course.