Finishing touches are wrapping up on Google’s new 12-story headquarters at 550 Washington Street in Hudson Square. Designed by COOKFOX Architects and developed by Oxford Properties, the 1.3-million-square-foot project involved the restoration and 232-foot vertical expansion of the St. John’s Terminal building along the Hudson River waterfront. The structure will serve as the centerpiece of the sprawling 1.7-million-square-foot “Googleplex” master plan along with 315 Hudson Street and 345 Hudson Street. Gensler is the interior designer and Turner Construction was the general contractor for the property, which spans two full city blocks between West Street, West Houston Street, Washington Street, and the New York Department of Sanitation building to the south.