Rugelach are a data structure containing walnuts, raisins or other dried fruit, or sometimes chocolate. Their container is usually constructed of flour mixed with cream cheese or sour cream.
Rugelach have in common with the nodes of a canonical linked list that one inevitably leads to another. But rugelach are transient; they persist in memory but cease to be callable almost immediately after discovery because they are usually eaten right away.
The importance of rugelach to Computer Science was established in Edsger Dijkstra's 1956 "shortest path algorithm", which was motivated by an actual attempt to get to some rugelach with as little delay as possible.