Figuring out the terms used in the documentation

[Sleep]

Thank you very much Adam, I have written a small diagram as an exercise, 
I would appreciate if someone could tell me if this is correct:

Display -> is ------> +---------------+
    |                  |   Server and  |
    V                  | Input Devices |
contains              +---------------+
    |
    V
Screens
    |
    V
  and a
    |
    V
Screen -------------+
    |                |
    V                V
contains         contains         +-------- which uses colors from
    |                |             |                      ^
    V                |             V                      |
Visuals <----+      |      Colormap* (and only one)    images**
    ^         |      |             ^                      ^
    |         |      |             |                      |
  from        |      |      is associated with <---    contains
    ^         |      +-----------                  \____  ^
    |         |                  \                      \ |
Visual    are associated with <- Windows -> contains -> Window
   ^                                                      ^
   |                                                      |
   +-----------------------------------------is associated with
*  Created out of a visual and window.
** Pixel format for 24 bit color depth visual is 0xRRGGBB,
    what is 8 bit color depth visual's format?