Ch4, Ex10

Well this is implementation dependent, Current behavior is completely in compliance with the symantics given in section 4.5.1 and lazy function is translated to ByNeed. Each call to {Three} creates a new trigger which is activated upon the need and in turn a thread is created that executes statements defined in function Three. But, in principle, its indeed possible to implement lazyness in a way so that value of a lazy function is calculated only ones upon the first time need and stored for later also.... as far as I know its called "memoization" .