Half of the people who enter “The Art of the Brick” exhibition will exit with one simple question: Why? Does the world really need its great works of art recreated in Lego bricks? Would Michelangelo or Monet or Vermeer approve of having their masterpieces rendered in a cheap, plastic children’s toy? Is this stuff even art? If you go “The Art of the Brick” is on display at the Denver Museum of Nature and Science” and will be included in regular museum admission through Labor Day.