Singley or doubley linked list? Edit: Just kidding, obviously singley. I am not a blockchain expert but don't agree with the "not at all" answer. The illustra

Singley or doubley linked list? Edit: Just kidding, obviously singley. I am not a blockchain expert but don't agree with the "not at all" answer. The illustration seems misleading, the nodes have nothing to do with the data structure, AFAIK blocks are only linked to previous block. I've always understood it as essentially a singly linked list where no list node can be removed without invalidating the entire list. Am I wrong?