The ring's source code in particular had to be transcribed from an actual shader I made (https://www.shadertoy.com/view/msd3R2). I didn't have the patience to write it directly in CSS. It's neither the right semantic nor the medium for it (which does make you wonder what CSS' medium was supposed to be).
Perhaps unsurprisingly, it runs at full 120fps on a decent laptop (it's just 21*21 JS style setting really). I've tried to make a half-JS, half-CSS version, and the speed is somewhere in-between. Basically, CSS variables are _extremely_ slow across all browsers, and I don't believe I've hit some particular edge-case. They're not used idiomatically here, but still, we shouldn't hit this drastic of slowdowns when updating 441 styles. They're also pretty hard to read the moment the calculation isn't some trivial basic arithmetics; and even then...
The true shader version runs at basically infinite fps =)
Yeah I was only talking about quantities. Equivalently, assume that it's a linear algorithm in the child and a linear one in the parent. Ultimately it ends up as O(nm) being some big number, but when people do runtime analysis in the real world, they don't tend to consider the composition of these blackboxes since there'd be too many combinations. (Composition of two polynomial runtimes would be even worse, yeah.)
Basically, performance doesn't compose well under current paradigms, and you can see Casey's methods as starting from the assumption of wanting to preserve performance (the cycles count is just an example, although it might not appeal to some crowds), and working backward toward a paradigm.
There was a good quote that programming should be more like physics than math.
It's more than that. The way black box composition is done in modern software, your n=100 code (say, a component) gets reused into a another thing somewhere above, and now you're being iterated through m=100 times. Oops, now n=10k
Generally, Casey seems to preach holistic thinking, finding the right mental model and just write the most straightforward code (which is harder than it looks; people get distracted in the gigantic state space of solutions all the time). However this requires 1. a small team of 2. good engineers. Folks argue that this isn't always feasible, which is true, but the point of these presentations is to spread the coding patterns & knowledge to train the next gen of engineers to be more aware of these issues and work toward said smaller team & better engineers direction, knowing that we might never reach it. Most modern patterns (and org structures) don't incentivize these 2 qualities.
...So none of these typical hand-wavy dismissals apply:
1. "Is it really faster for edge cases"
2. "He probably didn't implement certain features like Arabic and Chinese"
3. "Businesses just wants enough"
4. "Businesses just wants enough"
5. "It probably makes some closed-world assumption"
The performance of RefTerm didn't come from some big tradeoff; it came from using the right perspective and keeping things simple.
Sure, past a certain complexity threshold, you'd have to work for extra perf, but from my observations, folks who immediately jump to the wrong implicit conclusion that "good perf must have required compromises" got conditioned to think this way because the software they work on are already (often unnecessarily) complex.