One tradition that flourished 200 years ago in Japan, during its period of isolation from the western world, involved Euclidean geometry. Scholars and others would inscribe geometric problems on wooden tablets, then hang the tablets under the eaves of Shinto shrines and Buddhist temples as offerings. Such a tablet is called a sangaku, which means “mathematical tablet” in Japanese.
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More than 800 tablets have survived. Many of them feature drawings and problems that concern tangent circles.