On unbreakable rules

The idea of creating a model of interacting, free-form systems is ambitious. In order to keep it from being too ambitious and in order to introduce a rewarding, meaningful experience, there needs to be some written-in-stone rules that govern the systems I am creating. Here are the first few I have come up with:

1. A block cannot (directly) affect a block it is not (directly) connected to.
2. A block cannot (directly) affect or (directly) connect to itself.
3. Connections are governed by two things: definitions and proximity. Conditions set by both must be met for a connection between blocks to work.
4. System definitions are canon. If a definition of a system is not met, the system is broken and unusable.