Using GL_QUADS does not generate a rectangle

Hey, i’m currently trying to learn OpenGL and therefore I want to write a extremly simple pong game. I’m using Mac OSX 10.6.4 and Cocoa. This is what the output of the code looks like:

And this is my code:

@implementation OpenGLView
- (void)prepareOpenGL {
	glClearColor(0, 0, 0, 1);
}

- (void)reshape {
	CGFloat width = self.bounds.size.width;
	CGFloat height = self.bounds.size.height;
	glViewport(0, 0, width, height);
	glMatrixMode(GL_PROJECTION); 
	glLoadIdentity();
	glOrtho(0, width, 0, height, -1, 1);
}

- (void)drawRect:(NSRect)dirtyRect {
	CGFloat width = self.bounds.size.width;
	CGFloat height = self.bounds.size.height;
	
	glMatrixMode(GL_MODELVIEW);
	glClear(GL_COLOR_BUFFER_BIT);
	
	glColor3f(1, 1, 1);
	glBegin(GL_LINES);
	{
		glVertex2f(0, height/2.0);
		glVertex2f(width, height/2.0);
	}
	glEnd();
	
	glBegin(GL_QUADS);
	{
		glVertex2f(paddle1.offset, 0);
		glVertex2f(paddle1.offset + paddle1.width, 0);
		glVertex2f(paddle1.offset, paddle1.height);
		glVertex2f(paddle1.offset + paddle1.width, paddle1.height);
	}
	glEnd();
	
	glBegin(GL_QUADS);
	{
		glVertex2f(100, 100);
		glVertex2f(200, 100);
		glVertex2f(100, 200);
		glVertex2f(200, 200);
	}
	glEnd();	
	glFlush();
}

@end

I think this is not supposed to look like this, I just want a simple rectangle. Can somebody please tell me what I’m doing wrong?

thank you!

You must send the vertex in counter clockwise order.

A--------D
|        |
|        |
B--------C

OpenGl automatically split the quad in two triangles

A B C

A C D

Thank you very much. I guess that was a really stupid mistake.