> This can happen with any implementation of any class. From the definition of a square (a polygon with four sides of equal length) and we are trying to infer

> This can happen with any implementation of any class. From the definition of a square (a polygon with four sides of equal length) and we are trying to infer behaviour. But the definition does not require a square to remain a square after transformation; a square with a skew applied need not be a square nor a rectangle. Treating the square as a concrete class-based entity cannot capture this reality. You are correct, this could happen with any class.