Content can be flowed through one or more containers that can be laid out analogously to printed material. Content is flowed into the first specified container until that container is “full” of content. Subsequent content is then flowed through subsequent containers, each of which is individually identified, and whose ordering is specified independently of their position and visual presentation. Multiple independent sources of content can be flowed through multiple independent collections of containers. Each container can format the content presented within it independently from other containers, and each container can comprise script, or other programmatic constructs, which can operate on, and modify, the content flowed into such a container. To provide for the rich layouts, content containers can be nested inside one another such that multiple layers, or levels, of the layout can be edited independently of one another.