Sorry for the poorly written title, cannot think of how to write it better. I am looking for a word or phrase that roughly means "metaphorical environment". I'll explain:
The email system and protocols are designed based on the traditional snail mail system. For example the inbox works like a letter box where incoming mails reside. Then you may retrieve the mail from the letter box and sort them into folders at home, which you can similarly do on the email system. When you write a physical letter, you need to post it out, to somewhere, and we have the outbox for the same in an email system.
I want to express that the email system borrows ideas from traditional mail and is a "metaphorical environment", so if we think about the traditional mail system, we can better understand how email system works.
How can I express this in a proper sentence? Can I just say, "the email system is a metaphor of the traditional mail system"?