Hallo OP

We are interested in your work (the way how you did it) and would like to acquire it if it is not published somewhere else and when you are the owner of the work.
Send us a DM for further details if you like.

Rather simple.
You start in reverse meaning instead of adding random public keys to the starting pubkey, you find the final key and then start working your way backwards by subtracting the pub key (of the private key you already have) from the starting public key (which you don't have the private key of).