The photo series “Echolilia” began as a way for photographer Timothy Archibald to document and understand the rituals and other unusual behaviors of his five-year-old autistic son, Elijah. But Elijah soon became interested in the photographic process and became an active collaborator in the project. Over the course of the three-year project, father and son worked together to capture images of life with autism. The project is available as a photo book, Echolilia/Sometimes I Wonder. For more on “Echolilia,” see this Juventud Fotográfica post (translated into English over at Lomography).