The author optimized arcsin() calls in a ray-tracer by replacing a limited Taylor-series approximation with Padé approximants plus a half-angle transform (and a small [1/2] Padé for edges), yielding lower error and measurable speedups versus std::asin() across most of the domain. The post includes Python derivations and a C++ inline implementation used in PSRayTracing.

The author created a glitched, colorized version of the 1922 film Häxan by directly editing the h264 bitstream (hex). After two unsuccessful approaches (NULL-ing frames and injecting raw YUV noise), they settled on randomly flipping least-significant bits in I-frames biased toward chroma data, and provide a Python script (häx.py) plus ffmpeg commands to extract, glitch, and remux the video.