I had a recurring thought (again) the other day and again and again, it’s not very original however.  At first I thought I’d failed initially but I’m not so sure, especially after looking at Sanborn’s other works.  I thought by giving some visual examples it might help elucidate things…

Stand by the grey stone when the thrush knocks, and the setting sun
with the last light of Durin’s day will shine upon the key hole.

The Hobbit by JRR Tolkien (at 6 minute mark)

See also The Sun Lock of the Firebending Masters (at about 8:51 mark)

Perhaps some seasonally-based time-lock but perhaps with less dire consequences than the 1957 movie?

How about Indiana Jones using the Staff of Ra in the map room in the Raiders of the Lost Ark?

The Heelstone at summer solstice of Stonehenge?

There is also Almendres Cromlech, Arkaim, Woodhenge, the Ring of Brodgar…

Maybe the Kryptos Compass has some relationship to a sundial or gives some indication of seasonal time/alignment of the sun needed for a different part of the installment?  Maybe not.

Maybe I’m not crazy after all…