A celadon porcelain vase that imitates the shape of ancient Chinese jade congs. The vase was fired in the Southern Song Dynasty Hangzhou official kiln in the 12th century CE. Now housed at the National Palace Museum in Taiwan [1242×2276]

I recently visited the British Museum and saw a few of the originals. According to the museum, we don’t know what their purpose was.

The corner patterns are believed to be simplified mask motifs, which possibly represent a deity or mythological creature.

Christie’s has an interesting example [here](https://www.christies.com.cn/en/lot/lot-6237501).