model test {
   component comp (in i1, in i2, out o1) {
	   component sc1(in i1, in i2, out o1, out o2)
	   component sc2(in i1, in i2, out o)
	   i1 -> sc1.i1
	   i2 -> sc1.i2
	   sc1.o1 -> sc2.i1
	   sc1.o2 -> sc2.i2
	   sc2.o -> o1
   }
}