I have seen many data structures like stacks, queue, binary search tree, avl tree etc. Except stack and queue do we actually use these data structure outside the field of computers? Suppose I want to store by books(or any other stuff) according to some priority I would not use a binary heap to store my things, will I? I will just keep them in sorted order. So the question is - that are these data structures only optimal for computers or can they be used outside computers too?