Shape memory gels based on interpenetrating only part of one gel network with another gel network have been synthesized. These gels consist of two parts : a control element, which is responsive to a designated environmental stimulus, and a nonresponsive substrate element. By designing the pattern in the gelation process, a variety of shapes are obtained including "spiral," "square," "fish," "numbers," "alphabets," and "tube." The change between two different shapes can be controlled by external stimuli such as temperature and is reversible.