In everyday joint activities, people coordinate with each other by means not only of linguistic signals, but also of material signals – signals in which they indicate things by deploying material objects, locations, or actions around them. Material signals fall into two main classes: directing-to and placing-for. In directing-to, people request addressees to direct their attention to objects, events, or themselves. In placing-for, people place objects, actions, or themselves in special sites for addressees to interpret. Both classes have many subtypes. (...) Features of material signals were examined in pairs of people who were videotaped as they assembled TV stands, built Lego models, planned furnishings for a house, played piano duets, or bought coffee at Starbucks. In these activities, the pointing and placements were often sustained, creating three phases of signals – initiation, maintenance, and termination – each with its own interpretation. (shrink)