Mental model
A world in Blue is the set of blocks you participate in. Not one giant application — many separate interactions, each with its own participants, rules, and state, taken together forming your world.
Traditional software often assumes one app, one database, one owner, one interface. That makes "your world" equal to "everything you own." Blue is different.
You may participate in:
Each of those is its own block. Taken together, they form your world.
Alice runs a flower shop. Her world may include:
Bob, the customer, also has a world. From his side it includes the order block (Alice + Bob), the payment block (Bob + Alice + bank), the delivery block (courier + Bob), and his mandate block (Bob + Bob's agent). Bob does not see Alice's shop automation block, because he does not participate in it.
The bank sees the payment block (and PayNote rules attached to that transaction). It does not see the order details, the shop, or the delivery confirmation, except where those are explicitly composed into the payment.
You only need to understand the interactions you are part of.
Not every participant sees everything. Each block has its own participants and visibility model.
Blocks can reference or trigger each other, but they remain separate.
A participant may appear in many blocks, often through the same timeline identity.
Participation is per-block. A participant can be removed from one block (revoked from a mandate, removed from an order channel) but remain in others. Their world changes shape — the protocol does not. A world is not a single membership list; it is a per-block set of memberships.
Start with one shop. Then add an order, a payment, a service, a partnership, a refund flow, a recurring subscription. This is how "building reality" works in Blue — you do not build one monolith, you add new blocks to the world.
MyOS is one environment where worlds can be created and observed. But the world itself is not MyOS-specific. Blue blocks can, in principle, be processed elsewhere, hosted elsewhere, connected to other timeline providers, and moved across runtimes. That openness matters.