What makes an communication effective?  Simplicity. People are all busy, just tell them what's in it for them and don't make them thinking, and you can get an effective talk. Also in principle. Principles are words simple, but they conclude details, and make  power.  As  your good  beliefs changing  your  life, the OO design principles make the foundation of good programs. 
    Communication needs simplicity. Interaction changs the world.