objective-c As a local variable: returnType (^blockName)(parameterTypes) = ^returnType(parameters) {...}; As a property: @property (nonatomic, copy) returnType (^blockName)(parameterTypes); As a method parameter: - (void)someMethodThatTakesABlock:(returnType (^)(parameterTypes))blockName; As an argument to a method call: [someObject someMethodThatTakesABlock:^returnType (parameters) {...}]; As a..