Telephone is ultimate. Examining the strides in the evolution of communication, one who observed that the advanced one is based on the previous. Radio is simplex, which allows one person speaking to another person without reply. Now, the full duplex telephone allows many people speaking at once without one obstructing another. Internet is amazing, and we just access it through smartphone, advanced telephone. The evolution is interesting there are more to be discovered in the future.

Nice post @abix