OnThirdOrFourthLine implements Predicate { @Override public boolean at(short p) { return bits[p]; } private  OnThirdOrFourthLine(CoordinateSystem coords); static OnThirdOrFourthLine forWidth(int width); @Override boolean at(short p);  }
@Test public void atTest() { assertFalse(onThirdOrFourthLine.at(at("a1"))); assertFalse(onThirdOrFourthLine.at(at("a3"))); assertTrue(onThirdOrFourthLine.at(at("c3"))); assertTrue(onThirdOrFourthLine.at(at("q16"))); }