7-Segmented Parasol?

This is an 1801 engraving. Count carefully... her parasol has seven segments and seven struts. I am assuming that this is an artistic issue - I have never seen an uneven parasol. I see a lot with 8 struts, a lot with 6 struts, the occasional one with 4 struts (though not, in my experience, this early in the century). Artistic idiosyncrasy or unusual parasol - either way it is funky and interesting. Also, while we're at it, check out the beautiful back on the top engraving. So pretty!