public double getLightHeight() {
        return a;
    }
@Test
    public void examples() {
        assertThat("neutral", example(0, 0), is(0));
        assertThat("very much away from light", example(1000, -10000), is(-128));
        assertThat("exactly pointing at light", example(1 / algo.getLightHeight(), 1 / algo.getLightHeight()), is(127));
    }