This paper is a theoretical contribution to HCI that considers the more-thanhuman (MTH) as an intrinsic part of human-computer interaction design.In particular, it focuses on MTH as central to responses to the climate crisis as manifested in energy-demand reduction and smart meters.This is explored by expanding on the notion of the 'design event', defined aesthetically as the patterns or conformation of unfolding and becoming of heterogenous human and non-human elements.It is with this version of the design event that the MTH can be more directly and effectively engaged.We do this with reference to environmental problems as signaled by Haraway's speculative future 'the Chthulucene' -a worlding for liveable futures.The paper views design briefs in HCI, and design more broadly, as problematics for exploring and determining aesthetic-possible pathways for invention, which necessarily involves MTH elements.Three interrelated design briefs are presented that propose how practitioners might go about addressing energy-demand reduction and metering and provide a set of guidelines on how to devise and write speculative more-than-human briefs.This, the paper argues, involves becoming sensitive to speculative MTH compositions where novel forms of 'sense making' orient alternative possibilistic -idioticrelations to energy.

The Energy Babble is a kind of automated talk-radio that is obsessed with energy and the environment. We developed it with, and deployed it to, a number of existing "energy communities" in the UK. The system gathers content from a variety of online sources, including Twitter? feeds from the communities, from governmental departments, and from the National Grid, and chats about it continually using a number of synthesised voices interspersed with a variety of jingles and sound effects. Designed to playfully reflect and comment on the existing state of discourse and reports of practice in the UK, the Babble can be considered both as a product and as a research tool, in which role it worked to highlight issues, understandings, practices and difficulties in the communities with whom we worked.

The Photostroller is a device designed for use by residents of a care home for older people. It shows a continuous slideshow of photographs retrieved from the Flickr™ image website using a set of six predefined categories modified by a tuneable degree of 'semantic drift'. In this paper, we describe the design process that led to the Photostroller, and summarise observations made during a deployment in the care home that has lasted over two months at the time of writing. We suggest that the Photostroller balances constraint with openness, and control with drift, to provide an effective resource for the ludic engagement of a diverse group of older people with each other and the world outside their home.

Threshold devices present information gathered from the home's surroundings to give new views on the domestic situation. We built two prototypes of different threshold devices and studied them in field trials with participant households. The Local Barometer displays online text and images related to the home's locality depending on the local wind conditions to give an impression of the sociocultural surroundings. The Plane Tracker tracks aircraft passing overhead and imagines their flights onscreen to resource an understanding of the home's global links. Our studies indicated that the experiences they provided were compelling, that participants could and did interpret the devices in various ways, that their form designs were appropriate for domestic environments, that using ready-made information contributed to the richness of the experiences, and that situating the information they provided with respect to the home and its locality was important for the ways people engaged with them.

In a recent paper [3] H. Gaifman investigated some model theoretic consequences of Matijasevič's theorem [5], and posed some further problems which naturally arise. We provide here partial answers to two of these problems, the results having been previously announced in the postscript of [3]. Firstly, it is shown in [3] that if M1 and M2 are models of the Peano axioms P and M1 ⊆ M2, then M1 is closed under the recursive functions of M2. The converse of this statement is false. Moreover, Gaifman asks: Is every initial segment of a model M of P which is closed under the recursive functions of M (or the ∑n-definable functions) also a model of P? We show that this is false and our method gives, en route, another proof of a theorem of Rabin [7] stating the P is not implied by any consistent set of ∑n sentences for any n. Secondly, we partially answer a question posed on p. 129 of [3] by proving (some-what more than) every countable nonstandard model of P has an end extension in which a diophantine equation, not solvable in the original model, has a solution. We can, in fact, take the new model to be isomorphic to the original one. This generalises (apart from the countability restriction) a theorem of Rabin [6].