Ten months later... I've finished the Refraction construction video! There's a normal-speed version with commentary on YouTube at https://youtu.be/kmIe3VtLjc8. It shows geometry for major components, but like last time I didn't invest the huge time to capture extreme part-by-part of every construction step.
The music in this lightning-speed cut is from Castlevania: Dawn of Sorrow, composed by Michiru Yamane.