In an embodiment, an article comprises a plurality of structural units, wherein each structural unit comprises a first portion; a second portion; wherein the second portion contacts the first portion; and a third portion; wherein the third portion is in communication with the first portion and the second portion and is more compressible than the first portion and the second portion; wherein the first portion comprises a first shape memory alloy having a first preset state and wherein the second portion comprises a second shape memory alloy that has a second preset state; wherein the second preset state is different from the first preset state.