Olympic gold medalist Nastia Liukin paid a special visit to Trumbull’s Next Dimension Gymnastics center Tuesday, for an autograph signing with students. Liukin, who is in Connecticut to support the P&G Gymnastics Championships in Hartford, won five medals at the 2008 Olympics, including the gold for all-around competition. She has also earned nine World Championships medals. Liukin is now retired from gymnastics and attending college at New York University.