α, β, and γ are all angles. They can take any value, but all possible behaviors are represented by angles between 0° and 180°. I prefer the fractals produced when α = β (this introduces some extra symmetry in the image).
Letting the sketch continue to draw for a while will allow the colors to stabilize.
This is an implementation of the bi-axial hemispherical piecewise isometry (PWI) that I studied in my PhD research. See my paper on this PWI or my paper on getting meaning from the coloring for more detail.
You can find this sketch on the p5.js website as well to play around with it.