This cube focuses on the many different elements of graveyard interaction. Each color and card type has ways to interact and manipulate the graveyard.
Will you use the graveyard as a resource with mechanics like Delve and Flashback?
Do you want to stockpile your graveyard for Threshold or Goyf effects?
There are so many ways to reanimate creatures, return your permanents, or cast spells from the Graveyard.
If you want to ignore the graveyard and punish those that don't, there are plenty of graveyard hate cards as well.
From death triggers to artifact scrapping there are many ways to interact with the yard.