Mental model
The simplest way to understand Blue is to think of every interaction as a block — a shared interaction between participants, governed by rules, with visible state and a record of what happened.
Picture a single block. Participants sit around it. Timelines feed into it. Rules decide what can change. Current state is visible inside.
Who is part of the interaction: buyer, seller, payer, payee, guarantor, courier, service, agent, verifier, lawyer. Anyone with a role in the interaction is a participant.
What the participants can do: who may request a change, who may confirm a step, what conditions must be satisfied, what happens after an event, what is forbidden.
What is true right now: order status, current amount, delivery confirmed or not, refund window open or closed, approval pending or accepted.
What happened. In Blue, actions come through timelines. The block changes because a participant acted — and that action is part of a permanent record.
Today, interactions all have different shapes. An email thread is one kind of thing. A payment is another. A contract is another. A support ticket is another.
| Block | Participants | Rules | State |
|---|---|---|---|
| Email thread | Sender, recipients | Anyone in the thread can reply; sender can recall before send | Subject, messages, read status |
| Chess game | White, black | Only legal moves; alternating turns | Board, turn, result |
| Payment | Payer, payee, bank | When funds can be secured, completed, or reversed | pending → secured → completed |
| Order | Buyer, seller | Buyer can place; seller can accept; only ship after accept | placed → accepted → shipped → delivered |
| Mandate | Owner, agent | Agent must act within limits and conditions | active, allowed source, max amount, expiry |
| Service request | Customer, provider | Provider must accept; customer must approve completion | requested → accepted → in-progress → resolved |
Same idea. Different rules.
It is closer to a living agreement — a governed interaction with participants and rules.
"Document" is technically accurate. But "block" emphasizes self-contained interaction, composability, reusability, and structure. You can build worlds from blocks.