Just caught a glance at the planning notice for Twitter's expansion plans at the old SF Mart building between 10th and Market streets in San Francisco. This notice, posted on front of the building where Shorenstein property management plans to spend tens of million in renovations getting ready for Twitter and other tech companies in a new hub near City Hall, is required because the SF Mart is a historical building.
The notice (large photo) states plans to demolish the 9th story on the west side of the building to make way for "a roof deck with amenities including benches, planter boxes, and a green wall." I suspect the green wall will be something like this.
Here's one of my photos of the building as it is now: