: Build This phase can involve anything from low-tech methods such as paper prototypes and sketches, to more hi-tech and robust systems ready for long-term field testing. Whereas, before, much of the building within HCI has been essentially software-based, entailing the development of, say, an interface for a desktop or a mobile device, as we move forward to 2020, what we build may be more hybrid. It may require both development of the software interface plus novel amalgams of hardware. For instance, cameras may be used as an input mode, rather than a keyboard. It might, as another example, involve the creation of everyday objects such as furniture, or parts of the built environment such as special walls or floors. It might even involve no interface at all in the traditional sense. For example, micro-payment devices simply require proximity and no interaction – touching, clicking or pointing – at all. Some interactions are distributed across different parts of a physical-digital ecosystem consisting of various devices and interconnecting sub-systems.