The combination of two different kinds of skeuomorphs does not appear to be of very frequent occurrence, or, at all events, we have not yet trained ourselves to appreciate them.
In Fig. 50 we have an example, which, however, is not particularly satisfactory. It will be noticed that various kinds of plaiting are indicated on this Tongan club; as a matter of fact, if it had really been covered with plaited work, the latter would have been uniform in its character, although diverse patterns might have been worked into it. If this club had been decorated in a consistent manner the simple in-and-out plaiting of the broad band, as in the middle of the figure to the left, could not occur along with the finer oblique plaiting in other parts of the object.
Wherever two or more animals or plants are represented in association there is a tendency for them to amalgamate in process of time. I have shown numerous examples of this in the bird and crocodile motive in Papuan art, and it would be easy to multiply illustrations.
Heteromorphism is especially characteristic of that style of decoration which we call arabesque, or grotesque. This is said to have been the invention of a painter named Ludius in the reign of the Emperor Augustus. That sovereign is said by Pliny to have been the first who thought of covering whole walls with pictures and landscapes. The fashion for the grotesque spread rapidly, for all the buildings of about that date which have been found in good preservation afford numerous and beautiful examples of it. Vitruvius was entirely out of conceit with this sort of ornament, and declares that such fanciful paintings as are not founded in truth cannot be beautiful; but the general voice, both in ancient and modern times, has pronounced a very different opinion. It was from the paintings found in the baths of Rome that Raphael derived the idea of those famous frescoes in the gallery of the Vatican. His example was immediately followed by other distinguished artists. This style derived its name grotesque from the subterranean rooms (_grotte_) in which the originals were usually found--rooms not built below the surface of the ground, but buried by the gradual accumulation of soil and ruined buildings.