gistfile1.m

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    SEL selector = @selector(makeWonderfulWithString:number:);
    NSMethodSignature *methodSignature = [self methodSignatureForSelector:selector];
    NSInvocation *invocation = [NSInvocation invocationWithMethodSignature:methodSignature];
    [invocation setSelector:selector];

    [invocation invokeWithTarget:self];
    
    [invocation setTarget:self];
    [invocation invoke];
    
    NSString *string = @"Bingo";
    
    [invocation setArgument:&string atIndex:2];
    [invocation invoke];
    
    NSNumber *number = @4;
    
    [invocation setArgument:&number atIndex:3];
    [invocation invoke];
    
    string = @"Bongo";
    
    [invocation setArgument:&string atIndex:2];
    
    NSInvocationOperation *invocationOperation = [[NSInvocationOperation alloc] initWithInvocation:invocation];
    
    [[NSOperationQueue mainQueue] addOperation:invocationOperation];
    
    return YES;
}

- (void)makeWonderfulWithString:(NSString *)string number:(NSNumber *)number {
    NSLog(@"Wonderful with %@ and %@", string, number);
}