Biology
Oxygen–Hemoglobin Dissociation
S = pO₂ⁿ / (pO₂ⁿ + P50ⁿ), n ≈ 2.8

The sigmoid saturation curve of cooperative O₂ binding; the Bohr effect right-shifts it (raising P50) when CO₂ and acid build up, so hemoglobin unloads more oxygen in working tissue.
Computed & rendered in pure C# on the frozen OnlyCSharp 1.8 library — animation baked to GIF with the library's own
Gif encoder (no GPU, no ffmpeg, no external packages).