[ excerpt with modifications from developer's web site ]

Marbles tries to frame already existing items from different iconsets
to provide a consistent style for your desktop. Except the marble
design and a few newly created icons all pictures used are other
artists' stuff. This includes "art reuse" (as in "code reuse") of
crystal icons, slick icons, iKons, hicolor, Acqua and different
other ones found on kde-look. Thus the copyright/copyleft restrictions
of the original artists still apply. I deeply hope everybody agrees
with my attempt to unify the icon look for the rest of us who don't
have the time and skills to create their own complete, originally,
ground-breaking innovative theme.

WWW: http://www.kde-look.org/content/show.php?content=1581