Symmetry groups of Moroccan geometric woodwork patterns

Many works report the classification and analysis of geometric patterns, particularly those found in the Alhambra, Spain, but few authors have been interested in Moroccan motifs, especially those made on wood. Studies and analyses made on nearly a thousand Moroccan patterns constructed on wood and belonging to different periods between the 14th and 19th centuries show that, despite their great diversity, only five plane groups are present. Groups p4mm and c2mm are predominant, p6mm and p2mm are less frequent, while p4gm is rare. In this work, it is shown that it is possible to obtain the 17 plane symmetry groups by using a master craftsmen's method called Hasba. The set of patterns are generated from n-fold rosettes, considered as the basic motif, by the Hasba method. The combination and the overlap between these basic elements generate other basic elements. By repeating these basic elements, it is possible to construct patterns having various symmetry groups. In this article, only uncoloured patterns are considered and the interlace patterns are disregarded.