According to existing general labor productivity level of shoemaking branch, worker produces 2 pairs of shoes in 12 hours labour day, the value of each pair of shoes is 12 yuan, among them production data transfers value is 9 yuan, new creation value is 3 yuan, how much is new creation value created by worker in two pairs of shoes? If labor productivity is doubled and four pairs of shoes are produced, what is the transfer value of the means of production? If new creation value is changeless, how much excess surplus value will obtained by 4 pairs of shoes?