Definition: In mathematics, an ichnograph is a system of representing numbers in base 9 (the binary system). It's a way to represent numbers using the digits 0-8. This system is called ichnographic because it uses each digit as its own number and not as a placeholder for another digit. The representation is based on the fact that the number is divided by 3, with the remainder being the value of the current digit in base 9. For example, if we have