Claim: The poem titled Star Gauge, which refers to a spherical instrument used to calculate and predict the movement of planets and stars, features a circular poem which was written by Su Hui to her husband and circulated continuously until the Song Dynasty.
Evidence: The Star Gauge (Chinese: 璇玑圖), also known as Xuanji Tu ("Picture of the Turning Sphere") is a Chinese poem written in the 4th century AD. A star gauge was a spherical instrument used to calculate and predict the motion of planets and stars. The outer border forms a single circular poem, thought to be both the first and the longest of its kind. It was written by the poet Su Hui to her husband. The text of the poem was circulated continuously in medieval China and was never lost, but during the Song Dynasty it became scarce.