Give an example of why you would typically employ a number of architectural patterns while building the architecture of a complex system. What other information, in addition to the knowledge about...

Give an example of why you would typically employ a number of architectural patterns while building the architecture of a complex system. What other information, in addition to the knowledge about patterns that we have examined in class, may be relevant when developing huge systems? Also, what are two patterns that you would want to address with examples? Could you please elaborate?