Twice

 def twice1(func: Int=>Int)= (i:Int) => func(func(i));

 val add2 = (a:Int) => a + 2;
 val add4 = twice1(add2);
 
 println( add4(5));
 
 
 def twice2[T](func: T=>T)= (t:T) => func(func(t));
 
 val appendMark = (a:String) => a + "!";
 
 println( twice2(appendMark)("Hello"));