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Ed,

     This is a very interesting topic but it is obvious that absolutely no investigation was done before confidently proclaiming that this is the "world's first". I have a working digital sundial sitting on my windowsill from https://digitalsundial.com/ and have owned it since 2012. The concept was discussed long ago in the attached cartoon and more concretely by K. J. Falconer, "Digital Sundials, Paradoxical Sets, and Vitushkin's Conjecture," Math. Intelligencer 9, 21-27 (1987)
 https://link.springer.com/article/10.1007/BF03023569 and in the August 1991 edition of Scientific American https://www.scientificamerican.com/article/what-in-heaven-is-a-digital-sundial/

In the late 80's I toyed with the idea of building a holographic sundial (https://opg.optica.org/ao/abstract.cfm?uri=ao-29-32-4751 ). By shining a laser showing an image of digits onto white light holographic film from a specific angle you can in principle produce a hologram the shows different digits as the angle of illumination varies. We performed some experiments but the issue with building one in this way is that you need to make many exposures that will ultimately fog the film,

Regards,
Robin

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