Hybrid mana -- mana symbols that are typically split between two different colors -- are a commonplace in Magic: The Gathering. But that wasn't always the case.
In fact, for more than a decade of the game's existence, it never existed.
It wasn't until October of 2005 that hybrid mana made its first appearance. That was in the set Ravnica: City of Guilds.
It was the brainchild of MTG senior designer, Mark Rosewater, who was fascinated with the power of "or."
"When you look at a traditional gold card, it's an 'and' -- a red-and-green gold card is red and green," he explains. "I loved the idea of what did 'or' mean."
In short, thanks to the overlap between Magic's five colors, what did it mean for a card to be red or green, rather than red and green.
"So the idea was what if we could tap into that overlap space."
Rosewater talks much more about hybrid mana, how it was almost pushed back to a different set, and the power of "or" in the video below.