This paper presents a visual framework for organizing models of systems which allows a mixture of notations, diagrammatic or text-based, to be used. The framework is based on the use of templates which can be nested and sometimes flattened. It is modular and can be used to structure the constraint space of the system, making it scalable with appropriate tool support. It is also flexible and extensible: users can choose which notations to use, mix them and add new notations or templates. The goal of this work is to provide more intuitive and expressive languages and frameworks to support the construction and presentation of rich and precise models.