I had not thought about this before but earlier today I wondered if a link could be written vertically.

I did some experimentation with TextEdit on OSX and yes it can be written vertically as a clickable link. In my original TextEdit document the link is highlighted and underlined as a clickable link. When I saved as PDF it loses the highlighting and underlining but is still a clickable link. I attach the PDF.

Will do some more experimentation another time

André Schappo