final animation: http://www.youtube.com/watch?v=y6P1S8gr6d8&feature=youtu.be
http://www.youtube.com/watch?v=irCLczIt2Yg&feature=youtu.be
http://www.youtube.com/watch?v=Q5AipeXRm5M&feature=youtu.be
http://www.youtube.com/watch?v=96W-arwyVmI&feature=youtu.be
http://www.youtube.com/watch?v=Phrce3yivig&feature=youtu.be
Tower