John,
If "prior art" can be shown then any current patent claim can be
voided, this has indeed happened. As far as patenting a sundial design,
I would say don't bother. Firstly, it will cost you about $5k to file it
yourself and a lot more should you need to enforce it. I seriously doubt
any sundial designer could afford such litigation. A patent gives you a
legal recourse but not the cash to peruse it! If you want something nice
to hang next to your diploma(s) then go for it but it will cost AT LEAST
$5k, not that the diploma(s) were any less expensive...
-Luke
