LIGHT ON THE OBJECT · STUDY, NOT RULED
Two ways to make it three-dimensional
Neither draws the rosary. Both light it. Scroll — the light moves, the object does not.
ONE · RAKING LIGHT, CSS ONLY
A warm beam travelling the frame in mix-blend-mode color-dodge, its position a pure function of scroll. No script, no filter. The ground is darkened and the light does the revealing — 4.1’s field with a flame moving over it.
TWO · TRUE RELIGHT, SVG
A height map derived from the photograph drives feDiffuseLighting, and a fePointLight is moved by scroll. The highlights are computed against the surface, so they climb the beads and run along the arms of the crucifix instead of sliding over a flat picture. Real shading, in the browser, with no WebGL and no model.