 Ihde also recognizes a fourth type of human/technology relation in which technology is not directly implicated in a conscious process of engagement on the part of the human actor. Ihde refers to these as background relations. Examples include automatic central heating systems, traffic control systems, and so forth. These systems are ‘black-boxed’ in such a way that we do not attend to them yet we draw on them for our ongoing everyday existence. They withdraw as ongoing background conditions. Although he does not designate it as such one might formalize these relations in the form: I-[technology]-world. These invisible background technologies can be powerful in configuring our world in particular ways yet escape our scrutiny.