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2022-12-12   Fitts's Law and wormy Apples. In a UI, a big target can still be hard to hit.

2022-11-30   Apocryphon. An apocryphon is a self-decrypting text file.

2022-10-11   Making a laptop stand. With some reflections on the illusion of explanatory depth.

2022-07-06   The principle of orthogonal program code indentation. If indentation is really doing its job then it should be parsable.

2022-05-19   Factored radix numbers are a quasi-decimal alternative to higher-base numbers.

2022-04-01   Bioctal (RFC 9226) is an optimistic attempt to change the world, four bits at a time.

2022-03-30   Human factors alphabets for higher base numbers

2022-03-29   The ISO time machine is broken

Statestep is a tool supporting a simple tabular specification method designed to systematically elicit all unusual scenarios by making it possible to efficiently navigate large combinatorial spaces.

The approach supported by Statestep is described in Experience of using a lightweight formal specification method for a commercial embedded system product line (pdf). Requirements Engineering Journal 10 (2). Copyright 2005 Springer-Verlag. Author version. The original publication is available at

All Things Considered: Inspecting Statecharts by Model Transformation. On IEEE Xplore.

On Abstraction in Finite State Machine Models (pdf) is a short reflection on a cognitive issue relevant to finite state machine design generally.

Statecharts: Some Critical Observations (pdf). "Statecharts considered harmful."

A Note on Formal User Modelling in User Interface Design.

Notes on m4 - a comprehensive tutorial on the m4 macro language.

Other old content remains but is no longer linked from here pending possible updates.