Probably the best known rock-paper-scissors extension is rock-paper-scissors-Spock-lizard, as illustrated below. It's tolerably amusing, I suppose, if you happened to be trapped in a broken subway with four (other) sweaty nerds.
Tonight while playing rock-paper-scissors with the Hatchling during dinner, she was riding high on a string of 5 successive victories, when she suddenly innovated. My Smaller Half had played scissors - the Hatchling played a single extended finger.
"What's that? A sword?", I asked.
"No, a fish finger!", she said.
"Okay. So how does it work? What does the fish finger beat?"
"The goldfish", she replied, waving her flat hand held vertically, rather than horizontally as in paper.
"Right. And what does the goldfish beat?"
"Fish food!", she said, forming an inverted cup with her fingers pointing downward to the table.
"Okay, and what does the fish food beat?"
"What? There's not much incentive to play that then. Does anything beat the fish finger?"
A pretty bizarre variant - it's basically two parallel games. Rock-paper-scissors runs independently and as normal in its cyclical structure. And from time to time you can, if you wish, go skewing off into the fourth dimension and play the other fishfinger-goldfish-fishfood game, which is strictly hierarchical and entirely lacking in strategy of any kind. Basically if you're playing this game the fish-fingers stretch out in front of you to infinity unless you decide for some reason to deliberately throw the game by playing goldfish or fish-food.
As for what happens if there is cross-over between the two games, at this stage the science is unclear. Does fish-food beat paper? Do scissors beat gold-fish? I'd suggest treading carefully until the full ramifications have been worked out by the experts.
Nevertheless, as mentioned above, rock-paper-scissors-fishfinger-goldfish-fish-food captures some essential truths about life:
- it's repetitive,
- you cannot win, unless your enemy chooses to lose,
- you don't want to be fish food,
- nothing beats fish-fingers.
I think this is going to catch on and be a Big Thing. Might get some t-shirts printed.
But remember kids - don't play for money.