Update README.md

include/ftxui/README.md

@@ -1,31 +1,29 @@
-# 
+# Level of abstractions:
 * Level 0: terminal output.
 * Level 1: ftxui::Screen               
 * Level 2: ftxui::Node
 * Level 3: ftxui::Component
 
 ## Level 0: terminal output.
-  The terminal you know, you can append text on it. It is represented by
+  This is std::cout. You can send text to it.
-  std::cout.
 
 ## Level 1: ftxui::Screen               
   A rectangular grid of characters.
-  Use Terminal::ToString() to append its content into the console.
+  Use Terminal::ToString() to append its content to the console (level 0).
 
 ## Level 2: ftxui::Node
-  A hierarchical set of element.
+  A hierarchial set of element.
-  They handle layout and Render themself on the screen.
+  They handle layout and render themself on the screen (level 1)
   See ftxui/dom/elements.hpp
 
   You can make implement your own.
 
 ## Level 3: ftxui::Component
-  A hierarchical set of component. A component render itself by producing
+  A hierarchical set of components.
-  ftxui::Node in Component::Render().
+  Components store some state and react to events:
-
-  Some component can handle events:
     * keyboard
     * mouse
     * terminal event
+  Components renders themself by producing ftxui::Node (Level 2)
 
   Implement your own!