When they passed the new roundabout Thursday, Downtown workers glimpsed a preview of a major change that will be in place when they return to work Monday. The new precast concrete base that will support the statue of Andrew Jackson was being installed. The statue has been at the Landing since the riverfront mall was dedicated in 1989. On Saturday, the statue will be moved from its current location near the Hogan Street cul-de-sac to the center of the roundabout, marking the final step in the first phase of the Laura Street improvement project.