/---------+
|Model |
| |
| |
+---------+
^ ^
spec for | | manipulate
+----=-----+ +----=-----+
| |
| |
/---------+ /---------+ trigger /---------
|Spec | use |Action |<-----------|User |
| |<-----=------| | | |
| | | |----------->| |
+---------+ +---------+ response ---------/
| |
| | pmk [spec] -x action
+----=-----+ +----=-----+
spec for | | manipulate
v v
/---------+
|Data |
| {s}|
| |
+---------+