This is the triforce family crest (kamon) that Twitter user mahosyouzyo allegedly created after a relative passed away and was approached by her family requesting an updated design. You, uh, might want to be careful about which ocarina songs you go tooting around that memorial.
When another Twitter user told her that it looked like something from Zelda, she did, in fact, agree that it was a Triforce, although she claimed that she randomly drew it without much thought. Other denizens of Twitter were quick to point out that the Triforce seal resembles another Japanese Clan's kamon: the Hojo Clan. When asked about the similarity and if it would cause issues with the Hojo Clan, @mahosyouzyo pointed out that it is okay for different crests to resemble each other.
I dunno, based on the fact the girl tried to claim she came up with the design in the first place, it sounds to me like she just took a picture of a Hojo Clan (whose ancient crest is literally an exact triforce) memorial and is trying to pass it off on her own. Of course I could be wrong. I'm not, but I could be. In ancient times this sort of thing would have sparked an intense samurai battle.
Thanks to oblyvaeon, who wants a tombstone with a riddle on it. Intriguing! I want mine to read, 'My buddy Terry loved gravy.'