basic.m

void (^logMessage) = ^{
  NSLog(@"Hello from inside the block");
};

void (^sumNumbers)(NSUInteger, NSUInteger) = ^(NSUInteger num1, NSUInteger num2){
  NSLog(@"The sum of the numbers is %lu", num1 + num2);
};

for (NSString *word in funnyWords) {
  NSLog(@"%@ is a funny word", word);
}

[funnyWords enumerateObjectsUsingBlock:
  ^(NSString *word, NSUInteger index, BOOL *stop){
    NSLog(@"%@ is a funny word", word);  
  }
];

@interface Person : NSObject
@property NSString *firstName;
@property NSString *lastName;
@end