Internally driven solids

What is the long-wavelength, long-time dynamics of an elastic solid composed of motile orientable particles? Can different types of interactions between the motile particles lead to different varieties of active solid? What is the dynamics if the motile particles orient along a spontaneously chosen axis? Is it different from a passive solid which is driven externally? What if the inter-particle interactions instead favour aster-like configurations? I will present an answer to these questions and point out the differences and similarities between internally driven and externally driven solids.