Dark Souls message system where you have to write your messages using a library of constructed ideograms rather than your native language. You're allowed to build complex compound symbols by layering other symbols within each other or placing them alongside one another, and the game presents you with a few examples of this language in the environment to show you what sorts of constructions are possible.
However, very importantly, the game never at any point gives you a clear explanation of what any of the ideograms mean or presents you with a coherent grammar for them; the playerbase just has to figure out on their own how to use them. Maybe you represent "try illusionary wall" as [arrow pointing up-right] [rectangle [containing squiggles]] [eye], or maybe as [rectangle] [anguished face] [kiki]. It's on other players to interpret your message; maybe a consensus will form and maybe it won't.
in all seriousness: yes i want a dark souls language toybox version of symbol chat from pso 1, please