This paper describes a study of algorithmic living with Trace, a mobile mapping application that generates walking routes based on digital sketches people create and annotate without a map. In addition to creating walking paths, Trace enables people to send the paths to others. We designed Trace to explore the possibility of emphasizing guided wandering over precise, destination-oriented navigation. Studies of sixteen people's use of Trace over roughly one week reveal how walkers find Trace both delightful and disorienting, highlighting moments of surprise, frustration, and identification with GIS routing algorithms. We conclude by discussing how design interventions offer possibilities for understanding the work of mapping and how it might be done differently in HCI.