Part of a collection of 15th-18th Century French graffiti documented at the Chateau de la Roche-Guyon, France during the summer of 2018. Documentation done with Sony A7III and processed in Reality Capture from 187 photos. GDH ID Graffiti 7. Engraved stone. It could be a mason's mark or a graffiti. A Greek cross is represented, characterized by having arms of equal length. Its one of the most common Christian forms, in common use by the 4th century.