// prepare possible directions
        List<IDirection> directionGuides = Direction.DIRECTIONS_4;
        
        // prepare genetic algorithm engine
        Engine<IntegerGene, Long> engine = Engine
                .builder(MapWalker.FITNESS, new MapWalkerCodec(directionGuides, 5, 7))
                .build();

        // prepare genetic algorithm statistic
        EvolutionStatistics<Long, ?> statistics = EvolutionStatistics.ofNumber();

        // start engine
        Phenotype<IntegerGene, Long> result = engine
                .stream()
                .limit(500)
                .peek(statistics)
                .collect(toBestPhenotype());

        logger.info("\n" + statistics.toString());
        logger.info("Best fitness: {}", result.getFitness());
        
        // output result
        Cartographer cartographer = Cartographer.builder()
                .directions(directionGuides)
                .format(OutputFormat.HUMAN_READABLE)
                .data(result)
                .build();
        
        cartographer.output();
    }