public class Area {
    private Field[][] fields;

    public Area(int width, int height) {
        fields = new Field[h][];
        for (int y = 0; y < height; ++y) {
            fields[y] = new Field[w];
            for (int x = 0; x < width; ++x) {
                fields[y][x] = new Field();
            }
        }

        for (int y = 0; y < height; ++y) {
            for (int x = 0; x < width; ++x) {
                fields[y][x].setNeighbors(neighbors(x, y));
            }
        }
    }

    private ArrayList<Field> neighbors(int x, int y) {
        ArrayList<Field> n = new ArrayList<Field>();
        int xFrom = Math.max(x - 1, 0);
        int yFrom = Math.max(y - 1, 0);
        int xTo = Math.min(x + 1, width - 1);
        int yTo = Math.min(y + 1, height - 1);
        for (int yy = yFrom; yy <= yTo; ++yy) {
            for (int xx = xFrom; xx <= xTo; ++xx) {
                if (xx != x || yy != y) {
                    n.add(fields[yy][xx]);
                }
            }
        }
    }
}

public class Field extends Thread {
    private ArrayList<Field> neighbors;
    private int cost;

    public Field(int x, int y) {
        this.x = x;
        this.y = y;
        cost = 0;
    }

    public setNeighbors(ArrayList<Field> neighbors) {
        this.neighbors = neighbors;
    }

    public run() {
        // zablokuj wszystkie sasiednie pola 3x3 (neighbors)
        // jakies obliczenia ktore zmieniaja this i sasiednie pola
        // odblokuj wszystkie sasiednie pola 3x3 (neighbors)
    }
}