Another number system, which I learned about recently on HN, are the Kaktovik numerals, which are even closer to D'ni. Interestingly, they were developed just a

Another number system, which I learned about recently on HN, are the Kaktovik numerals, which are even closer to D'ni. Interestingly, they were developed just a couple of years before Riven was released. https://en.wikipedia.org/wiki/Kaktovik_numerals https://en.wikipedia.org/wiki/Kaktovik_numerals It's not a base-5 system exactly. It's base-20, where the rotated-and-superimposed digit is only one of the first three numerals. I guess you could call it a mixed-radix system, where the bases alternate like 4 5 ... 4 5 4 5 and where each group of 4 5 combines into a single symbol.