Then one day mathematician Søren Eilers was walking around Legoland in Denmark and was unsatisfied with the 102,981,500 number he saw on display. Sometime later, in his office at the University of Copenhagen, he set about working out the number for combining six two-by-four Lego bricks but factoring in the fact that the bricks could be placed next to each other as well as on top of each other. This was not a calculation that could be done by hand. Even with only six Lego bricks, the number of ways they can be attached to each other is too great to be counted by a human.
