/** Decode2.  2 input bits select 4 possible output lines.  */
CHIP Decode2 {
	IN s[2];
	OUT out[4]; // True iff a=b
	PARTS:
	Not(in=s[0], out=s00);
	Not(in=s[1], out=s01);
	And(a=s00, b=s01, out=out[0]);
	And(a=s[0], b=s01, out=out[1]);
	And(a=s00, b=s[1], out=out[2]);
	And(a=s[0], b=s[1], out=out[3]);
}