exercises 18. modelling rich interaction

	EXERCISE 18.3 Look again at the tea making task analysis in Chapter 15 (figure 15.4). Go through this and look for triggers and placeholders. You will need to make assumptions (e.g. is the kettle the kind that whistles when it boils?) so document these. answer available for tutors only		Other exercises in this chapter ex.18.1 (ans), ex.18.2 (tut), ex.18.3 (tut), ex.18.4 (tut) all exercises for this chapter