Construction of the ArcelorMittal Orbit (with a name that good it doesn't need a cute sobriquet) is well underway, as this video shows.
The swirling claret tower is already 70m tall, over half way to its 115m height, and if you've chanced your way around Stratford recently it's likely you'll have seen the emerging form compete with its neighbouring sports arenas for prominence on the east end's burgeoning skyline. Whether you regard it as visionary masterpiece or embarrassing folly, it's shaping up to be one of the dominant icons of the Games.
The Olympic Park Legacy Company have released the above time-lapse video which shows the tower under construction. There's also another video on their YouTube page showing progress over the last month; the latter video better emphasises the tower's current size when compared with the Olympic Stadium.
The tower is due to be finished in March 2012.