The Mexican artist Antonio Vega Macotela works with homogeneous groups, for example soldiers, miners or prisoners. With Time Divisa he has documented 365 ‘time exchanges’ with prisoners in the Santa Martha Acatitla prison in Mexico City where he offered them the possibility of exchanging actions. He asked them what they would like to do, but were unable to do because of their incarceration, and offered to do it himself. In exchange, the prisoners were to carry out the actions the artist requested. They then agreed on a day and a time when they would fulfil their respective commitments simultaneously. Vega Macotela was therefore able to see the first steps of a child, look for cult films, dance with a mother and go to brothels, among other actions. Meanwhile, the prisoners counted their heartbeats and noted their breathing rates, perforated a surface, or recorded the tempo of the steps they took as they listened to a song, and so on. The project, which lasted four years, presents a radically singular time-exchange system. Instead of the usual form of trading time for money, it explores the possibility of exchanging actions or fragments of life.