a walnut rostrum at the front of the chamber. Both the House and the Senate use computerized voting systems, including wall-mounted screens that allow visitors to follow the voting and both also contain glass tiled ceilings that allow natural light to shine through etched glass panels to better light the room. These ceiling tiles feature the coats-of-arms of each state in the United States. In summer 2013, the structure underwent additional work to replace carpeting installed in the 1989–1992 renovation that had become worn and frayed in many areas. Work also upgraded wiring for communications systems, repaired roof leaks and upgraded a handicapped parking area and entrance on the north side. Grounds The Capitol Pediment, located above the main front entrance to the building, is entitled "The Rise and Progress of Michigan." It depicts a central figure, Michigan, who is dressed as a Native American. She offers a book and globe to the people of her state, promising a bright future. She is surrounded by symbols of Michigan's economy, including a plow, cornucopia, and a laurel wreath to represent agriculture. Also included are symbols representing shipping, mining, and lumbering. The cornerstone, located at the northeast corner of the building, bears the dates 1872, the start of construction, and 1878, the year of completion. The stone was opened during ceremonies November 15, 1978, the centennial of the building's completion. Various documents enclosed within the stone had been damaged by moisture, although several coins from the era remained intact. Officials closed and resealed with stone with 38 new items depicting Michigan's history, people, and lifestyles. At the lawn's southeast corner is the Grand Army of the Republic Memorial, a 1924-bronze plaque attached to a boulder as a memorial to American Civil War veterans who fought for the Union. The grounds have several notable trees. An Eastern White Pine, the state tree of Michigan, is located at the east front of the building. The Dr. Martin Luther King Jr. Tree was planted in memory of the slain leader in 1984 to the north of the Austin Blair Monument. The oldest tree on the grounds is a catalpa on the southeast lawn present when the Capitol was dedicated in 1873. The American Forestry Association has certified this catalpa is the largest living tree of its kind in the United States. The most recently dedicated tree is a blue spruce called "the Freedom Tree," planted