Leonardo used both sides of the paper for his detailed studies of a dog's left forepaw. The paw, probably of a deerhound, is shown from a variety of angles. This is typical of Leonardo's analytical approach to the natural world, which he explored through extensive, and often annotated, drawings. Here Leonardo used metalpoint - a technique which required considerable control, for it was difficult to correct lines drawn with the metal (usually silver) stylus on specially prepared paper. The faint TL stamp, lower left, confirms the drawing, made around 1480, later formed part the drawings collection formed by the British painter Sir Thomas Lawrence (1769-1830).