BlockDAG
CasperLabs
One of the fundamental design choices that new projects may make is to build a DAG (directed acyclic graph) rather than linear chain (as it is done in Bitcoin or Ethereum). The idea behind building a DAG is that validators may build a blockchain "in parallel" (imagine multiple threads that originate from the same place, run in parallel but join at some point in the future to form a single thread again).
memo