Build Windows are used to create models in Vensim. By default, they open with the Sketch tools for sketching the structure of the model and for writing equations. The Status Bar provides buttons for modifying the sketch. Except in PLE models can be built from several different sketches or sketch views. Each sketch view shows a part of the model, much like each page in a book tells part of a story. In Vensim Professional and DSS, the Build Window can be switched to a Text Editor for building and editing text-based models. The Status Bar then switches to a text-editing version.