plus (+) operator implicitList += "Montana" println "Montana added with +: $implicitList" explicitList += ["Helena"] println "Helena added with +: $explicitList\n" The GDK List supports LIFO stack semantics with its List.push(T) and List.pop() methods, demonstrated in the next code example. // Demonstrate List.push() implicitList.push "Idaho" println "Implicit with push-ed Idaho: $implicitList"