def make_child(w1, w2)
  v1 = w1.path_vector
  v2 = w2.path_vector
  child1 = Path.new
  child2 = Path.new

  splitwood = v1.length / $cross
  slices_v1 = v1.each_slice(splitwood).to_a
  splitwood = v2.length / $cross
  slices_v2 = v2.each_slice(splitwood).to_a

  v1par = slices_v1.select.each_with_index { |v, i| i.even? }.reverse
  v1impar = slices_v1.select.each_with_index { |v, i| i.odd? }.reverse

  v2par = slices_v2.select.each_with_index { |v, i| i.even? }.reverse
  v2impar = slices_v2.select.each_with_index { |v, i| i.odd? }.reverse

  # cross
  while v1par.length > 0 || v2impar.length > 0 do
    if v1par.length > 0
      child1.path_vector << v1par.pop
#      pp = child1.pos
#      break if pp.x == 9 and pp.y == 0
    end
    if v2impar.length > 0
      child1.path_vector << v2impar.pop
#      pp = child1.pos
#      break if pp.x == 9 and pp.y == 0
    end
  end
  while v2par.length > 0 || v1impar.length > 0 do
    if v2par.length > 0
      child2.path_vector << v2par.pop
#      pp = child2.pos
#      break if pp.x == 9 and pp.y == 0
    end
    if v1impar.length > 0
      child2.path_vector << v1impar.pop
#      pp = child2.pos
#      break if pp.x == 9 and pp.y == 0
    end
  end

  # mutações
  mutations = []
  child1.path_vector.each_with_index do |d, i|
    if $random.rand(101) < $muta # 10% de chance
      mutations << {d: d, i: i}
      child1.path_vector[i] = $random.rand(0..3)
    end
  end
  child2.path_vector.each_with_index do |d, i|
    if $random.rand(101) < $muta # 10% de chance
      child2.path_vector[i] = $random.rand(0..3)
    end
  end

  return child1, child2
end