+ 'grob-value (* 2 1.5))
+@end example
+Instead of a successive symbol and value, an entry in the list may
+also be an alist or a music object in which case its elements,
+respectively its @emph{mutable} property list (properties not inherent
+to the type of the music object) will get taken.
+
+The argument list will be interpreted left-to-right, so later entries
+override earlier ones."