Create a real harmless non-electrical household object demonstrating Parameter Architecture. Supply two or three named user parameters with numeric values and units. Create one derived parameter with an expression and list the exact user-parameter names it depends on. Select a stable origin, baseline, datum or reference plane and explain it. Give exactly three steps, two measurable criteria, ordered minimum/nominal/maximum values, one invalid case and two limitations. Unknown licence remains quarantined and commercial use blocked. Forge execution is false. Supply all content yourself. JSON only.