Ilyas came to the addiction clinic through Hamid and Vincent, two field workers from Jellinek. Tonight the two men drive around the city. They start in Leidsche Rijn at the Haarrijnse lake. They slowly drive into a parking lot. “They often have the lights on and the windows are usually fogged up,” Hamid explains. “You can tell immediately when they use it, because then you see a balloon through the window.”