f all the artwork Cubs manager Joe Maddon has introduced to his players this spring, the most powerful display appeared Thursday at Marlins Park during batting practice before the Cubs’ 8-4 victory. In a walking exhibit of empathy, Cubs players wore maroon T-shirts with “Stoneman Douglas” on the back and “#MSDStrong” on the front, an opening-day tribute to the 17 victims of the Feb. 14 shooting at Marjory Stoneman Douglas High School in Parkland, Fla. Maddon’s foundation, “Respect 90,” purchased the shirts for the Cubs.