1) Nico Schlotterbeck
Although his superb in-swinging corners could have in theory happened with any formation, it is hard to argue that Schlotterbeck is one of the Dortmund players suited to playing in a three at the back the most.
The German defender has a very modern profile. He is quick and good on the ball. Owing to these capabilities, he has played as a left back at times in his career. There have sometimes been criticisms of him defensively, particularly inside the box.
In this set up, playing as the left sided central defender in a back three - he is able to defend the channels, which his mobility allows him to excel at, and he is also able to carry the ball forward and play passes between the lines.
Furthermore, whilst as mentioned above, he could have played those corners in any formation - having an extra centre back to aim for, as a result of the three at the back set up, only adds to Dortmund's threat from set pieces.