2) Rewarding extended investment. Artefacts should be
designed such that prolonged or repeated exposure should
yield deepening engagement, whether through revealed
complexities, or by encountering a greater breadth of
creative stimuli [13]. While extended engagement should
uncover more of interest, we did not want casual encounters
to somehow feel incomplete. Accordingly, we concerned
ourselves with artefacts which manifested a variety of
behaviours, any one of which might offer some intrigue, but
where extended curiosity uncovered more of the picture,
without there being a sense that there was a hidden goal,
which might frustrate if not discovered [see also 3].