I had noticed that there are different versions of this on the pirate flags, such as the crossed swords on the flag associated with the Pirates of the Caribbean. Also, had remembered seeing a red bandana with polka dots on the Hook Wreck Henry's sign - the one that says "Surrender the Booty." (The Dockside Cafe owned by my Charlie's friend Jason Walker from High School in Tallahassee).
It seems that in the 15th century or thereabout, great sailing and trading vessels were on the high seas, and as a matter of national pride and pride in the ships, they began displaying flags with certain patterns and colors, some of which then became the national flags of the nations of their origins.
Of course pirate ships started plundering these ships, and developed their own flags - mainly as a way to terrorize and intimidate the ships into submission without much of a fight. The first ones were red , signifying blood, and then came the black ones, indicating death to all who don't surrender.
The term "Jolly Roger" is thought to be derived from the French "jolie rouge" (pretty red) or from the word "rogue," which describes a vagabond beggar or thief. Another thought is that it is a derivation of the English colloquialism "Old Roger" which was an English slang term for the Devil.
Different pirate related emblems are thought to have been used by different famous pirates for identification of their ships, as "Calico Jack," a fearsome guy who roamed the Caribbean, used the crossed swords under the skull instead of the bones. This one was used in the movies "Pirates of the Caribbean."
Anyway, the histories I found were quite interesting and rather amusing - so try it yourself if you like! As for me - the images and stories I found have almost motivated me to design some more skull type things to thrill ghoulish little grandsons. I also have a grown-up type son, who is a successful and dignified (most of the time) attorney, who still loves pirates and Halloween. He might like a pillow of this sort on his throne in his den at home. (in front of the TV)