a, Stimulation of different patches of skin on the stump evokes sensations referred to different digits. The mapping can in principle be exploited to achieve tactile feedback that is more intuitive. b, Mechanical stimulation of the chest, to which nerve fibres have been rerouted. The stimulation elicits sensations referred to the phantom limb, and often to the phantom hand174. Credit: Image courtesy of Kenzie Green; panels adapted with permission from ref. 28, Foundation of Rehabilitation Information (a) and ref. 42, Elsevier (b)