RxJava and Java 8 Game of Life

ReactiveGameOfLife.java

import rx.Observable;
import rx.functions.Action1;
import rx.subjects.BehaviorSubject;

import java.awt.*;
import java.util.Arrays;
import java.util.List;
import java.util.function.Function;
import java.util.stream.Collectors;

public class ReactiveGameOfLife {

    private static class Iteration {
        final int generation;
        final List<Integer> cells;

        public Iteration(int generation, List<Integer> cells) {
            this.generation = generation;
            this.cells = cells;
        }

        Iteration next(List<Integer> cells) {
            return new Iteration(generation + 1, cells);
        }
    }

    public static void main(String[] args) {
        // Some stats about the playfield
        int width = 6;
        int height = 6;

        // The initial state and something to load it into a List of Integers
        String initial = "......" +
                         "......" +
                         "..###." +
                         ".###.." +
                         "......" +
                         "......";
        Function<String, Integer> isAlive = s -> s.equals("#") ? 1 : 0;
        List<Integer> state = Arrays.asList(initial.split("(?!^)")).stream().map(isAlive).collect(Collectors.toList());

        // Something to print out out playfield
        Action1<Iteration> printer = l -> {
            System.out.println("GENERATION " + l.generation);
            Observable.from(l.cells).map(c -> c > 0 ? "#" : ".").buffer(width).map(s -> String.join("", s)).forEach(System.out::println);
        };

        BehaviorSubject<Iteration> subject = BehaviorSubject.create(new Iteration(0, state));
        Action1<Iteration> loop = i -> {
            printer.call(i);
            Observable.range(0, i.cells.size())
                    .flatMap(idx -> Observable.range(0, 9)
                            .map(off -> new Point((idx % width) + (off % 3) - 1, (idx / width) + (off / 3) - 1))
                            .filter(pt -> pt.x >= 0 && pt.x < width && pt.y >= 0 && pt.y < height)
                            .filter(pt -> pt.x + pt.y * width != idx)
                            .reduce(0, (a, p) -> a + i.cells.get(p.x + p.y * width))
                            .map(score -> score < 2 || score > 3 ? 0 : (i.cells.get(idx) == 1 || score == 3 ? 1 : 0)))
                    .toList()
                    .subscribe(cells -> subject.onNext(i.next(cells)));
        };
        subject.take(10).subscribe(loop);
    }
}