Final answer:
The symbol referenced as a sleeping 8 number is the infinity symbol, representing a concept without end or limit and is used metaphorically in various literary contexts to express the vastness of existence and time.
Step-by-step explanation:
The question 'I am endless and boundless. I look like a sleeping 8 number. What am I?' refers to a symbol known as the infinity symbol. In mathematics, this symbol is used to represent a concept that has no end or limit. It resembles a sideways figure eight and it is often used to express something that is unbounded or cannot be quantified.
The infinity concept is also used metaphorically in various contexts, as seen in the excerpts provided. These excerpts from literature explore themes of the unknown, the sense of something greater than oneself, and the vastness of time and existence. The infinity symbol and these literary extracts both allude to the idea of something that is limitless or without end, be it time, life, or the universe.