Short write‑ups of problems we hit running a real commerce operation and what we changed in the code because of them. No product announcements; just the reasoning.
The same candle is one thing to the buyer, a box of twelve to the warehouse, and a litre of base to the factory. aiku models that with three corners — the trade unit (the physical thing), the stock (that thing, in this warehouse), the product (that thing, as sold in this shop) — and a number on every edge. Why a fraction is sometimes right and sometimes a bug, and why changing a number on an edge while an order is in flight is the most dangerous edit in the system.
The group catalogue — 62,000 master products feeding 317,000 shop products across 34 open shops — is where a thing is described once and pushed to every shop that sells it, so that in theory one person at one desk can run the lot. Majors and minors for multi‑currency prices, a "follow the master" switch at three levels, the scalar column we are retiring because it silently mixed currencies, and a price cascade that ran for a month multiplying RRPs by pack size before a repair put 1,635 values back.