Workers were applying a mural Thursday to one of the arched windows on the historic Barnett Bank Building along Laura Street. The rendering depicts the building as it will look when it is fully renovated and restored, said Steve Atkins, manager of Barnett Tower LLC, which acquired the building for $3 million one year ago in partnership with Stache Investments, a company led by Jacksonville Jaguars owner Shad Khan. Atkins said the mural is the first of several that will be installed, including some that won’t be unveiled until Wednesday to celebrate the kickoff of One Spark.