I can confirm that originally the Snake was not displayed in the diagram that Jörg posted. I looked at the page source, and the diagram was a direct link to the diagram generator, which did contain the S in the intended square in the CGI parameter. But no show... But now it magically appeared, with the same browser (FireFox). There must have been something temporarily wrong on the server, such that the server-side script could not find the Snake image file to compose the entire image.
I can confirm that originally the Snake was not displayed in the diagram that Jörg posted. I looked at the page source, and the diagram was a direct link to the diagram generator, which did contain the S in the intended square in the CGI parameter. But no show... But now it magically appeared, with the same browser (FireFox). There must have been something temporarily wrong on the server, such that the server-side script could not find the Snake image file to compose the entire image.