Oh I get it now. There a torus-like surface would be precisely, which would have needed other shade bending, probably blurring and clipping.
Tried not to use blurring for such effect, because the yellow object could be made with that too.
That was the main part, to showcase the trick -adding a 3D look without colouring spots one by one.
Not that it couldnt produce, or produce an even more polished/stylish feel, but this way changing the lightsource can be done anytime on the filtered parts.
About the effect, I do understand that it can look as an overblown nonsence, and crawl the system.
Glad you tried to open the svg. By looking at the download count, people in general seem not realising the brute-force behind to make the filter work.
Should have made something more complicatedly looking. But sadly this was only on my mind, and the effort put inside it was enough for me.
Added a new article on the general technic at
inkscape community, will be up soon hopefully.
-edit: here it is:
http://forum.inkscapecommunity.com/index.php?action=articles;sa=view;article=24-
Also, have split apart that yellow part and uploaded the svg to openclipart, this may give a better insight:
https://openclipart.org/detail/203126/bent-pencil-effect-by-lazur-urh-203126