What do you think bathtubs, showers, sinks, taps, doors and most fittings are? There is a ton of prefabrication in construction already. There are also large l

What do you think bathtubs, showers, sinks, taps, doors and most fittings are? There is a ton of prefabrication in construction already. There are also large libraries of shared details. Most of the bits that are not already prefabricated are the bits that don't have simple interfaces. Either to each other or to their surrounding environment.