Solution:

The first level is divided to eight parts, second floor has ten similar frame, for the third level we can see nine similar frame, fourth floor has eight and the fifth level has seven similar frame. Then we can make a generic conceptual mass model as a family for each frame and it should have changeable instances for its window’s frame size and position. A simple equation can be used to control the size of the window and limit it to the size of the frame. In addition the window frame must be inside the frame so it movement should become limited to the frame size.

The whole designing process can be find bellow.