Figure 1. The Virgin of the Rocks, attributed to Leonardo da Vinci, National Gallery, London, 1503-1506.  Note the homogeneous structure of the rocks extending upward, as well as the hard edges that give them an artificial look.  The massive rocks in the foreground display no geological detail.  The flora is also diverse throughout the picture.  The plants in the foreground resemble cultivated annuals which need considerably more light than world be available in the grotto.

Virgin of the Rocks, National Gallery, London, 1503-06