I am wondering about Smart Contracts: as such, they reside inside the Blockchain, this means they have to be stateless. If the state of a SC changes (i.e. changing the value of a variable), the hash value of the overall SC changes and as a consequence the Blockchain is broken.
So, where is the stateful data stored? Or does it mean that each time stateful data (i.e. value of variables) change, the same SC will be stored again and again on the Blockchain, meaning a multitude of instances of the same SC?