and_gate(In1,In2,Out) :- In1,In2,Out=true,!.
and_gate(_,_,Out) :- Out=false.
or_gate(In1,In2,Out) :- (In1;In2),Out=true,!.
or_gate(_,_,Out) :- Out=false.
tri_gate(In1,In2,In3,In4,Out) :- 
      and_gate(In1,In2,X),
      and_gate(In3,In4,Y),
      or_gate(X,Y,Out).