Vending machine Karnaugh map

The dispense signal is shown as a compact four-variable Karnaugh map rather than a long list of binary inputs. The concentrated ones in the right-side columns make the grouping choices easier to discuss with a digital-logic class. This visual does not replace the input definitions: A through D should be documented as the actual credit, selection and stock conditions used by the circuit. After grouping adjacent cells, test the reduced expression against every input combination, including conditions where a product is unavailable. Before sharing it, compare the chart with the source table and make the scope explicit. A clear date range, population and unit help another reader interpret the pattern correctly and decide whether follow-up analysis is needed.