The wiring language is simple because domain-specific behaviors are NOT in the wiring diagram. The wiring language can't even do arithmetic. That's OK, because arithemetic is domain-specific behavior.

     Domain-specific behaviors are built by developers, and are easily accessed from the wiring, through Visual APIs, which you will see later.

     I’m using yellow arrows here to indicate domain-specific behaviors that are being kept out of the wiring language.

     The yellow components I’ll be adding to the wiring are gateway components that open up graphical APIs to domain objects.