An independent interactive learning resource adapting concepts from W. Ross Ashby's An Introduction to Cybernetics (1956). Authorship of the original book belongs to Ashby; the modern exercises are adaptations.
Open the root application, choose the chapter, then the named exercise. The application does not implement stable exercise URLs.
Chapter 3 · 12 exercises
Describe states and follow transformations
Explore whether a state description is sufficient to predict the next state. Compare transformations, closure, trajectories, basins, equilibria and cycles; distinguish a phase plot from a time plot, determinism from reversibility, and convergence from finite arrival. Vector updates happen simultaneously.
Try this question: Would two systems with the same recorded state always have the same next recorded state?
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Compare in the atlas: Modelling · Observer
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Chapter 3 exercise collection
Chapter 4 · 17 exercises
Investigate inputs, coupling and boundaries
Inputs select transformations, and different controls may produce the same result. Test clamping, coupling, rewiring, transients, delays and reachability. Compare a diagram of component dependencies with a graph of complete states. What counts as input or output depends on the chosen boundary.
Try this question: Which boundary makes this quantity an input, and which graph answers your question?
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Compare in the atlas: Boundary · Feedback · Modelling
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Chapter 4; Whose input is it?; Two graphs, two questions
Chapter 5 · 13 exercises
Test what stability means
A set can remain stable while its members continue to move. Explore closure under composition, stability relative to specified disturbances, neutral equilibrium and bus bunching. The sign of a feedback loop alone does not establish the stability of the whole system.
Try this question: Stable with respect to which disturbance, and over which set of states?
Open the app and choose chapter 5
Compare in the atlas: System Stability Principle · Feedback · Negative feedback
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Chapter 5 stability exercises, including bus bunching
Chapter 6 · 14 exercises
Learn from a black box without inventing its behaviour
Build observation protocols and choose experiments that distinguish competing accounts. Keep unknown transitions unknown and distinguish inaccessible states from untested ones. Compare isomorphism with coarse-graining, test which distinctions a weak model loses, and use observation history when the current recorded state is insufficient.
Try this question: Which next observation would distinguish the models, and what has your simplification hidden?
Open the app and choose chapter 6
Compare in the atlas: Black box · Isomorphism across systems · Observer · Modelling
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Chapter 6; A blank is not a self-loop; Choose a revealing experiment; Why this simplification breaks; Let yesterday reveal a hidden state
What has been checked
56 exercises across chapters 3–6 and 45 glossary entries. Public content.js, app.js and engine.js inspected; full interactive correctness and accessibility testing are not claimed.
The app covers chapters 3–6. It is not a complete reproduction of the book. Requisite variety, the Good Regulator theorem, ultrastability and the Homeostat are not presented as demonstrations in this application. Editorial comparison links do not establish historical influence or equivalence between accounts.
Links and original editorial descriptions only. No unrestricted code licence was established; no app code, diagrams, answers or substantial source passages are reproduced.
Ashby Laboratory · Compare the separately attributed Challoner researcher modules