Here is a picture of the simple "Rect" object:

                                         Rect 
                                     o-------------o     
                                     |             |
                                     |  > height   |
                                     |  > width    |
    Rect class variables/methods --->|  > area()   |
                                     |  > perim()  |
                                     |             |
                                     |             |
                                     o-------------o