This is the image, a Hebrew signature about which I'll write in the next post.
And this is a selection from the first page of results:
Just to summarize the results: Not only did Google Image Search not find another exemplar of this insignia, but it seems to think it is a cross between the strokes of Chinese calligraphy and the curvature of a toilet seat. Partly this is a problem of the image just not having been uploaded to the internet for Google Images to find. But it's also clear to me that the visual search engine needs a good bit of tweaking before it can be useful for paleographic or codicological searches.
To be continued.