Variable structure system

A variable structure system (VSS) is like a puzzle that you can rearrange. In this puzzle, each piece (or "variable") is made up of a few different pieces itself. Each of these smaller pieces have different properties and can fit together in different ways. In a VSS, these pieces can be used to make different structures that can do different things. For example, if you wanted to build a robot, you could use a VSS to create a structure with legs, arms, and a head that could move around and interact with its surroundings.