A designer may be assigned responsibility for implementing a structural part of the system (such as a class or
implementation subsystem), or a functional part of the system, such as a use-case realization or feature that crosses
It is common for a person to act as both implementer and designer, taking on the responsibilities of both roles.
It is possible for design responsibilities to be divided, such that a high level sketch of the design is the
responsibility of one designer, while detailed design (such as details of operation signatures, or the identification
and design of helper classes) is deferred to another designer who also acts as the implementer.