A flour mill app Avai wrote for a single customer, who was once dad's good friend (from work, I'd guess, him being the chief agroengineer in the village) and whose son was my first student, when I was jobless in 1980 and he had trouble with maths on electrotech college. The app never took off - I was too enamored in the exchange concept I introduced in Acc157 and just reworked it for this, which was not enough on one hand, and too complicated on the other. Not sure whether we gave the money back, but the app didn't see much use.