I took these yesterday. It has changed a lot already since simms posted his shots.
They are building up from the back:
I didn't shoot it from the other side but on the webcam you can see that the bulk of the steel has been installed in the back (away from Fremont) half. Basically up to the taller column to the left of the crane below. They will eventually fill in to the large column peeking out on the far left:
And to the corresponding column on the far right of the site:
I am way too excited about this building.