I cannot delve him to the root.

a distributive numeral, such as Latin bini (two by two)

That is mentally—outsidely, but not insidely. You have not relaxed down through your body at all.

Queue implementations are commonly based on insertion order as in first-in, first-out (FIFO) queues or last-in, first-out queues (LIFO queues are also known as stacks).