Yang Hui
Around 1275 AD, Yang finally had two published mathematical books, which were known as the "Xugu Zhaiqi Suanfa" () and the "Suanfa Tongbian Benmo" (, summarily called Yang Hui suanfa ). In the former book, Yang wrote of arrangement of natural numbers around concentric and non concentric circles, known as magic circles and vertical-horizontal diagrams of complex combinatorial arrangements known as magic squares, providing rules for their construction. In his writing, he harshly criticized the earlier works of Li Chunfeng and Liu Yi (), the latter of whom were both content with using methods without working out their theoretical origins or principle. Displaying a somewhat modern attitude and approach to mathematics, Yang once said: