Physigrams are a way of  modelling the interactive behaviour of a physical device ‘unplugged’, that is the things you can press, prod, push, twist, stroke, or pull, but ignoring what they do digitally.

In this section:

A physigram is a variant of a state transition network (STN) where the states represent physical states of the device, and the transitions the things you can do to it.  Here is one of the simplest physigrams for a simple rocker-style light switch.


Often a physigram is linked to a description of the logical state of the device, which may be electrical (as in the case of the light switch) or digital.  Here is the switch physigram linked to the light’s behaviour.

This is a particularly simple class of behaviour, a one-to-one mapping, but the linkage may be more complex.

For more about physigrams see the following publications:

A. Dix, M. Ghazali, S. Gill, J. Hare and D. Ramduny-Ellis (2009). Physigrams: Modelling Devices for Natural Interaction. Formal Aspects of Computing, Springer, 21(6):613-641  abstract and links

A. Dix and M. Ghazali (2017). Physigrams: Modelling Physical Device Characteristics Interaction. Chapter 9 in The Handbook of Formal Methods in Human-Computer Interaction, Springer, pp.247–271.  DOI: 10.1007/978-3-319-51838-1_9