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Anyone who has tried to assemble a piece of furniture from Ikea or Wal-Mart knows that describing the instruction manual as "medieval" is far too kind. However, a researcher at the University of Warwick in England thinks medieval builders had a superior system for conveying construction information on everything from Gothic churches to Tudor houses.

Mason's marks, instructive symbols inscribed directly onto dressed stone, have been used for 4,000 years. The marks allowed builders to translate the design of the master mason without need of written directions. They were also used to identify which mason worked on which part of a building, which would help determine payment.