Chicago Spire

[truetifoso]

Does anyone know what technique was used to build Adam Tucker's Chicago Spire?

http://pix.alaporte.net/pub/d/30803-1/L ... e-up+2.jpg" onclick="window.open(this.href);return false;
http://31.media.tumblr.com/tumblr_letfb ... o1_500.jpg" onclick="window.open(this.href);return false;
http://media3.washingtonpost.com/wp-srv ... 239717.jpg" onclick="window.open(this.href);return false;

Thanks in advance.