Hinterland – a poem that you play – ran for two weeks at the Edinburgh festival. Over four cantos, players would seek out strangers meeting particular criteria (which varied per canto), and get them to help answer a questionnaire. Then, players would phone the Operator, and hand over their answers. The Operator wasn’t a human being, though: it was a piece of software. I wanted to write a little about the technical design behind the game: how we wrote a game for telephones, and the design considerations that went into it.