The "useful paper" you're referring to is a community-created for the adult game Harem Island (v1.0a), developed by ERONIVERSE .
In the ever-expanding universe of adult visual novels and sandbox simulation games, few titles generate as much whispered excitement as Harem Island . With the recent release of its build on the Eroniverse platform, the game has officially sailed out of early alpha and into a content-rich, stable experience that fans of the genre have been clamoring for. Harem Island -v1.0a- -Eroniverse-