Enumerate a list of object specified in a prototype with NS_REQUIRES_NIL_TERMINATION. From http://cocoawithlove.com/2009/05/variable-argument-lists-in-cocoa.html

NIL_Termination.h

- (id)initWithTitle:(NSString *)title 
           delegate:(id)delegate
    animationImages:(UIImage *)firstImage, ...NS_REQUIRES_NIL_TERMINATION;

NIL_Termination.m

- (id)initWithTitle:(NSString *)title delegate:(id)delegate animationImages:(UIImage *)firstImage, ...{
    if ((self = [super initWithFrame:CGRectZero])) {
        va_list args;
        va_start(args, firstImage);
        
        NSMutableArray *images = [[NSMutableArray alloc] init];
        
        for (UIImage *arg= firstImage; arg != nil; arg = va_arg(args, UIImage*)) {
            [images addObject:arg];
        }
        
        _title = [title copy];
        _animationImages = [images copy];
        _delegate = delegate; //weak assign
        _visible = NO;
        
        va_end(args);
        [images release], images = nil;
    }
    return self;
}

NIL_Termination_Call.m

NewObject *new = [[NewObject alloc] initWithTitle:@"Loading..." 
                                         delegate:self 
                                  animationImages:[UIImage imageNamed:@"1.png"], 
                                                  [UIImage imageNamed:@"2.png"], 
                                                  [UIImage imageNamed:@"3.png"], 
                                                  [UIImage imageNamed:@"4.png"], 
                                                  [UIImage imageNamed:@"5.png"], 
                                                  [UIImage imageNamed:@"6.png"], nil];