Table 1.
A summary of the ostrich eggshells fragments from the HP.
Fig 1.
Map of the HP sites with EOES.
Basemap: CARTO, © OpenStreetMap contributors, CC BY 4.0.
Fig 2.
A synthesis of a spatial and chronological assessment of the EOES motifs.
Data elaborated from Texier et al. [2]; Heshilwood et al. [3]; Jacobs et al. [29]. We have associated the two fragments from Apollo 11 to the ‘sub-parallel intersecting lines motif’ as, in our statistical analyses, they display the same values in terms of regularity of line alignments, consistent with the fragments in the same category from Diepkloof.
Fig 3.
Example of tracing of a fragment (modified from Texier et al. [2], Figs 8 and 3b), normalization of the engraved lines, and data extraction.
Fig 4.
PCA biplot of the EOES fragments showing clusters of geometric patterns highlighted in yellow and red.
Fig 5.
Positive outliers in the multiple regression analysis.
These cases show a low degree of alignment strategies.
Fig 6.
Negative outliers in the multiple regression analysis.
The engravings exhibit an extremely high level of regularity in terms of parallelism. D49 shows significantly high structural consistency also in terms of minor angle degree.
Fig 7.
Repertoire of the operations underlying the ‘geometric grammar’ in the EOES.
These operations illustrate the geometric primitives and the embedding processes identifiable in the EOES motifs (1: hatched band; 2: grid; 3. diamond shape). This image was the result of a pseudo-code (plain language algorithm) in S2 Document.
Fig 8.
Examples of EOES motifs with positive and negative Moran’s I.
Fig 9.
Variations in motif composition on the EOES.