Reciprocity means the quality or state of being reciprocal: mutual dependence, action, or influence. This project explores the interaction between two different objects in daily life, which have contrary properties but always be used simultaneously. On the one hand, the first category, such as bowl, sofa, and bed, originally has fixed and stable status, representing relative eternity. On the other hand, the second category, such as kitchen tissue, blanket, and quilt, is easily changeable and flexible in terms of the shape, which has temporary quality. Furthermore, when each group of objects, like the bowl with kitchen tissue, combines, the whole appearance demonstrates stable but relatively temporary characteristics. People can see the bowl's profile from the shape of the tissue, but the tissue, even the entire appearance of the new combination, can still be mutative based on the different positions or relationships. They interact with each other, affect the other one, and finally being reciprocal.