Mason's marks (Steinmetzzeichen) are symbols carved by stonecutters on dressed stone. These signs go back about 4500 years. In Europe, one can mainly find quarrier's marks from the medieval ages. In Architectural History, stonemason's marks allow to reconstruct the construction process of a building. Mason's marks can be concisely represented by planar line graphs using basic Computational Geometry. This text shortly introduces mason's marks and the implementation of the software tool VanDeGraphGenerator to draw, analyse, and generate graphs in the declarative programming language Constraint Handling Rules. This book then features sixty choice mason's marks from Ulm Minster, Strasbourg Cathedral, and Iglesia Arciprestal de Santiago in Spain. Exploiting the inherent structural regularities of mason's marks, VanDeGraphGenerator can assemble new designs automatically using methods from Artificial Intelligence research to achieve a kind of Computational Creativity. The main part of the book showcases more than thousand new designs produced by the tool.

Thom Frühwirth is a professor of Computer Science at the University of Ulm, Germany. His research areas are Computational Logic and Constraint Programming. He is the designer of the logical formalism and programming language Constraint Handling Rules. http://www.constraint-handling-rules.org