With admitted limited knowledge of advanced mathematics and computer programming, the following is my understanding of the phenomenon also known on E2 as Pile on nodes. According to one source, nodes have something to do with trees, the worst case ..."which looks like a linked list."
Further explanation states..."every node has max 2 children...labeled as left or right...Left has precedence over right"...Totally unfair and slightly prejudicial. Going from bad to worse, ..."items are added...and there is no rebalancing," which sounds somewhat like my washing machine's problems with heavy loads. However, that is followed by..."in which case you have a string of n nodes."
I am uncertain who labels or maintains Pile on nodes on E2 or if there is another official explanation somewhere. Picture included for another usage if you like visuals, can read Chinese or are curious. If anyone else would care to add to this, do a nodepile or message me with your comments.