My chest like any harpy’s, and my face

Patched like a carpet by my dripping brush.

Nor can I see, nor can I budge a step;

My skin though loose in front is tight behind,

And I am even as a Syrian bow.

Alas! methinks a bent tube shoots not well;

So give me now thine aid, my Giovanni.

Fig. 67.
‘Draw upon part of wall MN half the figure you mean to represent, and the other half upon the cove above (MR).’ Leonardo da Vinci’s Treatise on Painting.

At present that difficulty is got over by using large strong canvas, on which the picture can be painted in the studio and afterwards placed on the wall.