D'ni numerals
D'ni numerals overview
D'ni numerals are a fictitious base-25 counting system used by the fictional D'ni race and seen in the two computer games Riven, Uru: Ages Beyond Myst and Cyan's Myst novels.
To fully appreciate the D'ni number system, it is suggested that you do NOT read this article or look at the accompanying picture until you have finished Riven. A significant part of the Riven endgame is locked until the player has deduced the meaning of the symbols as numerals, and their values.
Also, the numerals make a cameo appearance in Myst 3: Exile. The meanings of numerals one through eight are presented much more straightforwardly in the Relto Age in Uru: Ages Beyond Myst.
The image to the right from Garternay.com gives you a basic idea of this system. The numerals 1, 2, 3, and 4 are rotated by 90 degrees to yield the numerals 5, 10, 15, and 20 respectively. (This principle of Fives misleads many to believe that D'ni numerals are base-5.) These eight numerals are combined to yield numerals for all the numbers zero through twenty-four.
Two additional numerals, a 25 (an 'X' with the square box) and a "cyclical zero" (a forward slash with the square box), are commonly used for special purposes.
