Here is a link to a tutorial I recently gave on direct acyclic graph (DAG) based consensus protocols at a16z. In this talk, I introduce DAGs, which allow blocks to have multiple parents or children, thus resolving the problem of “forks” in blockchains. The resulting structure is a Directed Acyclic Graph (rather than a chain). I show how to think about such structures and then focus on state-of-the-art protocols such as Cordial Miners, DAG-Rider, and Bullshark.
Link to talk