My first social media (in 2014). And he could go forward the arroward network, from his own private card, only throught these 4 links to see the "private cards" of the others users. It's like a 2D grid mapping between all users.
Disclaimer : Sorry guys, no pattern design are intentionnaly followed ; i worked as a beginner. I built it as a website, from scratch, with few developpement tools. And worst, SQL DB is missing. Because i lost the backup and the schema :( but i think that retro engineering about that issue won't be so difficult to do). But the concept is cool.