Is it possible to write a contract for an existing ERC20 contract?

Question

Cryptocurrency

Hello. There is an ERC20 token and, of course, its native contract.
In general, in the category for this existing contract, is it possible to write your own contract?
That is, that we communicated with my contract with the original contract?
In more detail, now there is a surge of pyramids (classic MMM) operating on the air. You send Ether, and in a day you receive % from the payment.
In theory, can this be done for an ERC20 token?
I communicate with a potential developer, shows an example of a contract. In which the contract of the original contract is duplicated (with which a bundle is needed) and + followed by my "Wishlist".
As I understand it, such a contract is just a copy of a dummy.
Which is autonomous and independent, tokens from such a mix are not original and cost absolutely nothing.
Enlighten please.

Answer 1

Well, of course you can, how do you think altcoins are processed by contracts?