I really really hate websites that hijack my back button. Come on pc-gamer, do you really think that making me click two extra times on the back button to return where I came from is going to make me spend more time on your site?
I feel like nobody understands what Turing completeness really means anymore, i.e. why this is kinda amusing but also not really remarkable.
Back in the day people did ray tracing by hand on calculators, in PostScript (yes, the document description language used by printers), ... ray tracing is really simple, a basic exercise in vector maths, so we should expect to see it everywhere.
Is it for fun? If so, great. Not my cup of tea personally, but I can imagine how it could be someone's.
If not for fun, what is the point? It presumably isn't to create a usable ray-tracing system. Perhaps a challenge to improve the author's Excel skills? If so, I suggest they move on to a proper programming language and visualisation system.
There seems to be this obsession, among some people, with using Excel for all sorts of inappropriate things, and I have a sinking feeling that this might be related to that. A system for generating contracts using Excel formulas, in Excel, instead of using mail merge, or something else, with Word or something else designed to format prose text, is a horrible example I have come across at work.
NVidia are bringing out a hardware spreadsheet accelerator card this Fall (mainly for Excel but it'll work with any spreadsheet app). This is one of the example sheets to show off how fast it is.
I see what the author is doing as part of the demoscene. Many people enjoy programming in limited environments, learning how to optimize, and pushing it to the limit. No one is actually going to use this in a product; its just art.
Perhaps that's what it's about today, but when it actually started back in the days of the C64 and 300 baud modems it was about pushing the tech to its limits just to see what it could do. Generally the only people who would actually see it would be people who downloaded a pirated game and had the demo play before the game started.
Crazy excel project though, well done.