As a form like this can't be SuDivided directly (Top face more than 5 edges)
All Plugins by Max Smirnov

Use SSPlit for trim
Use SBridge for "Blend Faces" only 2 by 2
Use _SUbD for SubDivide




Copy / Move faces
Bridge them



Extrude to Point or Nsided (Kill the caps before) can be used for simple form :)