if (a.length != b.length)
throw new IllegalArgumentException(String.format("WireArray width does not match: %d, %d", a.length, b.length));
this.a = a;
// this.b = b;
a.addObserver(this);
b.addObserver(this);
if (a.length != b.length)
throw new IllegalArgumentException(String.format("WireArray width does not match: %d, %d", a.length, b.length));
this.a = a;
// this.b = b;
a.addObserver(this);
b.addObserver(this);