In Freemasonry the sword pointing to the naked heart is a symbol that demonstrates that justice sooner or later will over take us . And yes I've seen a pirate flag in one of my books on pirates that does look similar to that symbol . Pirates used many flags , it is a fallacy that all pirate ships flew the skull and cross bones , they flew flags of their own design . Take Edward Teach's( Blackbeard) flag , his flag was a skeleton with horn's holding a hour glass in one hand and a spear pointing to a bleeding heart in the other .