In classical texts, two short horizontal lines "𖿣" are often used to indicate reduplication.
In cursive script, it is written as "〻" and standardized as "々"1.
In the simplification of Chinese characters, this "reduplication symbol" has been used multiple times, such as:
- 棗 → 枣
- 饞2 → 馋
Outside of Chinese (in Japanese new characters):
- 澀 → 渋
The variant character "澁" for "澀" was simplified, where the four flying dots at the bottom actually represent two reduplication symbols, indicating that this is a "three-reduplication character" structure.