designer's own words:Form which users desire The units of PLUS YOU are separated one by one. Therefore, you can just assemble it again to the form that you want and use it suitably. For example, when mothers use it with a child, they can use it by making it fit for 2 people. When there are 2 children, it can be made for 3 people or assembled and used for 4 people. In the guardian’s point of view, this saves the wasted, unnecessary effort from the subject that always needs to be close and protected, and in the protected one’s point of view, it allows slightly more free movements, but is enough to always give them the feeling that they are protected.