//1. creating NSMutableSet with some NSArray.
    NSMutableSet *set1 = [NSMutableSet setWithObject:[NSArray arrayWithObjects:@"Aston Martin",
                                                      @"Lotus", @"Jaguar", @"Bentley", nil]];
    [set1 addObject:[NSArray arrayWithObjects:@"Aston Martin1",
                     @"Lotus1", @"Jaguar1", nil]];
    [set1 addObject:[NSArray arrayWithObjects:@"Aston Martin2",
                     @"Lotus2", @"Jaguar2", @"Bentley2", nil]];

    //2. Retrieve All Objects from NSMutableSet
    NSLog(@"print for NSMutableSet1 - %@",[set1 allObjects]);

    //3. Retrieve combined all objects from NSMutableSet
    NSMutableArray *resultArray = [[NSMutableArray alloc] init];
    [set1 enumerateObjectsUsingBlock:^(id obj, BOOL *stop){
        [resultArray addObjectsFromArray:(NSArray*)obj];
    }];
    NSLog(@"result array - %@",resultArray);