Hehe good question. ๐ Exists 3 ways how i founded this clock product.
1. I am slovak in czech republic and here every glass manufacturer knows between each other.
2. In my work we did on this

and we was learning very much informations about glass casting and gas inside. Every gas has another light colour and we was founding 2 layer of glass to combine together.
https://en.wikipedia.org/wiki/Gas-discharge_lamp
And this is answer how we found him and his work. We had plan to visit him but corona changed our plans. ๐
3. I did for my friend poster for programing contest and now we are creating this stature in real. We bought nixie tubes in chine and now we do 3d print. I rendered in keyshot and did big postproduction in affinity photo.

crop ๐

it is not a very good how yours. ๐