Did I miss something with Syntax?

So basically I have been trying to keep up with the video's syntax for creating button shapes, although Xcode will not allow me to create them cause it says "circle" is an undeclared variable. Although I have exactly all the syntax exactly as the video in "main.m".

So since the syntax is the same, the only conclusion I can come to think of is that the instructor may have changed a bit of the syntax of circle classes from the previous video called Inheritance. Since in this video he had also added a new class for rectangles.

Shown bellow is my code in main.m (I can't compare Circle.h cause he doesn't show it in the Composition video):

#import <Cocoa/Cocoa.h>
#import "Shape.h"
#import "Circle.h"
#import "Button.h"
int main()
{

    Shape *shape = [[Shape alloc]init];
    NSLog(@"shape area %f",[shape area]);

    Circle *round = [[Circle alloc]init];
    NSLog(@"cicle area %f",[round area]);

    Button *roundButton = [[Button alloc]init];
    roundButton.shape = circle;


    return 0;
}

Am I just missing something obvious cause I'm cramming too many hours and am missing something obvious? or is there really a difference of class codes within the two videos. Any feedback will be greatly appreciated! : )