🧪 Supply Chain Demand Forecasting Simulation

This simulator makes the bullwhip effect visible: a four-echelon chain — retailer, wholesaler, distributor, factory — each forecasts the order stream it receives with exponential smoothing and replenishes toward a safety-stock target, exactly as real inventory-management systems do. Because every echelon reacts to a one-period-old, already-smoothed signal instead of true customer demand, mild and steady end-customer buying turns into wildly swinging factory production orders purely from the mechanics of forecasting and re-ordering — no external shocks required. Tune the forecast smoothing constant, the order-up-to aggressiveness and the customer's demand volatility, or inject a one-off demand shock, and watch live inventory towers and order-history bars at each stage show exactly where and how the amplification builds.