![File:China, Neolithic period - Perforated Disc (Pi) - 1915.628 - Cleveland Museum of Art.jpg - Wikimedia Commons File:China, Neolithic period - Perforated Disc (Pi) - 1915.628 - Cleveland Museum of Art.jpg - Wikimedia Commons](https://upload.wikimedia.org/wikipedia/commons/6/61/China%2C_Neolithic_period_-_Perforated_Disc_%28Pi%29_-_1915.628_-_Cleveland_Museum_of_Art.jpg)
File:China, Neolithic period - Perforated Disc (Pi) - 1915.628 - Cleveland Museum of Art.jpg - Wikimedia Commons
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![Jade bi or pi disc, China, Han dynasty, 206 BC - 220 AD, Stock Photo, Picture And Rights Managed Image. Pic. HEZ-2362013 | agefotostock Jade bi or pi disc, China, Han dynasty, 206 BC - 220 AD, Stock Photo, Picture And Rights Managed Image. Pic. HEZ-2362013 | agefotostock](https://previews.agefotostock.com/previewimage/medibigoff/80e7acce9dff7006d2b4788f29ab09cd/hez-2362013.jpg)