> Great write-up! Your speedups look like they line up as expected. Would you happen to know why Aras's look a bit weird, is it the devices he's using? I'm referring to his Metal timings being more than 10x slower than D3D, and being almost comparable to C++.

Thanks for reading! Since Aras is using a GTX 1080 TI on Windows, and an Intel Iris Pro on Mac, I think the numbers make sense. In my case, my GTX 770 is pretty old, and my 2017 MacBook is pretty new, so the numbers line up better.

> It's a fun exercise in ShaderToy to write a recursive ray tracer. Here's mine: https://www.shadertoy.com/view/XllBRf

> And here's a much better one: https://www.shadertoy.com/view/4scfz4

Nice! I should add accumulation to mine -- it'd look much better for barely any effort.