by Needham, but adds that recent research has revealed a document which lists the names of those who allegedly built an iron chain suspension bridge in Yunnan around the year 600 AD. T Tangram: The tangram is a dissection puzzle consisting of seven flat shapes, which are put together to form shapes. The objective of the puzzle is to form a specific shape using all seven pieces, which may not overlap. The game is reputed to have been invented in China during the Song Dynasty, and was popularized in Europe and United States during the 19th century. The word tangram is likely derived from two words, the Chinese word tang, referring to the medieval Chinese Tang Dynasty, and the Greek word gramma, a synonym of "graph". Tea: The tea plant is indigenous to western Yunnan; it is thought that by the mid 2nd millennium BC, tea was consumed in Yunnan for medicinal purposes, but the earliest physical evidence (discovered in 2016) comes from the tomb of Emperor Jing of Han dated to the 2nd century BC. Tea drinking was already an established custom in the daily life in this area as shown by the Contract with a Slave, written by Wang Bao in 59 BC, the first source to mention boiling of tea. This written record also reveals that tea was processed and used as a drink instead of a medicinal herb, emerged no later than the 1st century BC. Early Chinese tea culture began from the time of Han Dynasty (202 BC – 220 AD) to the Southern and Northern Dynasties (420–589) when tea was widely used by Chinese gentry, but only took its initial shape during the Tang Dynasty (618–907). Teapot: The teapot was invented during the Yuan Dynasty, tea preparation in previous dynasties did not utilize a teapot. In the Tang Dynasty, a cauldron was used to boil grounded tea, which was served in bowls. Song Dynasty tea was made by pouring water boiled using a kettle into a bowl with finely ground tea leaves. A brush was then used to stir the tea. The innovation of the teapot, a vessel that steeps tea leaves in boiling water, occurs during the late Yuan dynasty. Written evidence of a teapot appears in the Yuan Dynasty text, Jiyuan Conghua, which describes a teapot that the author, Cai Shizhan, bought from the scholar Sun Daoming. By the Ming Dynasty, teapots