What progress did chairs make in the Song Dynasty?

Chairs in the Song Dynasty gradually improved and became more and more popular. The wooden chair unearthed from Julu site in Hebei Province is1.13m high and 0.59m wide. The chair is engraved with ink, indicating that Chongming was in the Northern Song Dynasty for three years. The four legs of the wooden chair are all made of logs, slightly outward, and the feet are connected by straps similar to the forehead. High backrest micro-arc inward, no handrails. Chairs, backrests and handrails unearthed from the Song Tomb in Luzhou, Sichuan are all round. Song Dynasty chairs unearthed in Zunyi, Guizhou, have bird heads carved on both ends of the crossbar on the back.