This is a reusable implementation of the omnipresent design pattern "Observer".
Note, that a well designed program in Object Teams will usually not require an explicit Observer infrastructure. See the Stopwatch example for an example, how a plain callin-binding (4) suffices.
This demo should, however, give a quick understanding to some techniques of Object Teams for all who are familiar with the Observer pattern (the OTDT ships with a simpler version of this pattern).
||This implements the GoF pattern very straight forwardly.
Open spots are:
||Implement some base entities|
||Two applications of the Observer pattern
binding the above open spots using callin (4) and callout (3) bindings.
||A simple main program|