private enum PopulationState {
        DONE_X0Y0Z0(new Vec3i(0, 0, 0)),
        DONE_X0Y0Z1(new Vec3i(0, 0, 1)),
        DONE_X0Y1Z0(new Vec3i(0, 1, 0)),
        DONE_X0Y1Z1(new Vec3i(0, 1, 1)),

        DONE_X1Y0Z0(new Vec3i(1, 0, 0)),
        DONE_X1Y0Z1(new Vec3i(1, 0, 1)),
        DONE_X1Y1Z0(new Vec3i(1, 1, 0)),
        DONE_X1Y1Z1(new Vec3i(1, 1, 1));

        private Vec3i vec3i;

        PopulationState(Vec3i vec3i) {
            this.vec3i = vec3i;
        }

        static PopulationState fromVec(Vec3i v) {
            int ordinal = v.getX() << 2 | v.getY() << 1 | v.getZ();
            return PopulationState.values()[ordinal];
        }
    }