If you think about trust
Why checking costs more than generating, and where the fix lives.
Zach Shallbetter’s notebook. A question on my desk right now:
What, exactly, is an interaction?
The trail so far
My working theory →
01Featured system Open source
Fundamental Engine
Making relationships computational.
A cross-platform runtime where objects, relationships, forces and constraints are explicit, inspectable and computational, and an ongoing research program exploring the boundaries of computational systems.
- 01 Declare Define bodies, relationships, forces and constraints. See the model →
- 02 Influence Let the field resolve behavior through explicit rules. Watch it run →
- 03 Read Access state, metrics and evidence at any point. Inspect state →
- 04 Reveal See how behavior emerges and why it changes. Explore examples →
- 05 Govern Set boundaries, authority and what can change. Learn more →
02Featured book Judgment Machines
The Last Undo
How we know enough to act.
A practical framework for establishing what must be true before a decision becomes materially harder to reverse.
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01
The question
Find the last place a mistake is still cheap.
Read the introduction →
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02
See the cost
Why faster output still means checking by hand.
In the book →
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03
Find the seam
Locate where reversal becomes costly.
In the book →
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04
Carry the proof
Record what was established, and by whom.
In the book →
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05
Measure the claim
State the limits and what would change the conclusion.
In the book →
03Featured system Azimuth
Azimuth
Reality before rendering.
An evidence-aware physical-world runtime in development. Explore what exists, how it changes, and what an observer would actually perceive.
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01
Observe
Bring observations and modeled data into the same world.
Learn more → -
02
Resolve
Keep evidence, derived state and uncertainty distinct.
Learn more → -
03
Simulate
Address the scene by time, rather than a playback position.
Learn more → -
04
Inspect
Ask where a representation came from and what it supports.
Learn more →
Where to start reading
31 essays. Choose a route, or follow one current thread.
If you make physical things
What a factory teaches software, and what software gave back.
If you design interfaces
From the open question of interaction to a product built on one rule.
If you lead people
Accountability, hiring and community as infrastructure.
Current threads
2026Distance from GrayA commitment-specific account of what remains unestablished, and what contracts and measurement can show without pretending to prove truth.2026Why Interaction Became a Scientific ProblemFour decades of human-computer interaction, and the question the field kept postponing: what, exactly, is an interaction?2026The Material Is the ContractWhat building a nano-ceramic game board taught me about parameters.2026Living DocumentationThe input-side contract for generative work.Working through a problem that crosses disciplines?
I help carry the work from figuring out what needs to happen through design, engineering and delivery.