Another idea, use the color of your t-shirt as a random number source. If you know electronics, you may use https://en.wikipedia.org/wiki/Electronic_color_code , it's easy to remember because it's almost as a rainbow. And pick ((color(x)+color(y))%3)+1 or something.
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Ideally we'd use nothing besides ourselves, but dice is a good idea.
Another idea, use the color of your t-shirt as a random number source. If you know electronics, you may use https://en.wikipedia.org/wiki/Electronic_color_code , it's easy to remember because it's almost as a rainbow. And pick ((color(x)+color(y))%3)+1 or something.