The formation of nuclei of oxidized and dark material on a film of reduced, compacted and clear material was followed from electrochromic films of different conducting polymers, providing that this type of nucleation is a general fact of those materials, as established by the Electrochemically Stimulated Conformational Relaxation model. When the nucleation is stopped at any intermediate state of the nuclei growth, by switching off the polarization, the reduced and clear regions are oxidized at expenses of the oxidized ones. Any intermediate and uniform colour is attained by switching off the polarization at different times, proving the non-stoichiometric nature of the oxidized material. That means that any intermediate composition can be attained and that infinitesimal changes of the composition are possible. Any property of the material linked to the composition also will change in a continuous and infinitesimal way. Those infinitesimal changes linked to the reverse electrochemical reactions are strongly influenced by any physical or chemical change: here we present a tactile sensing artificial muscle.