more text for README.md

README.md

@@ -24,6 +24,18 @@ gwbuild -jNN (with NN number of parallel processes, e.g. 4 for quadcore cpu)
 sudo gwbuild -i
 ```
 
+## Structure of AqDiagram
+
+AqDiagram consists of 4 parts:
+- data:
+  Library for data manipulation (accumulate, negate, diff, average, floating average)
+- draw:
+  Library for drawing text and simple figures (points, lines, rectangles), current implementation for libcairo).
+- placement:
+  Library for placement of objects in a plane.
+- graph:
+  Library for drawing graphs using the other libraries.
+
 
 ## Code Examples