Use the adjective schematic to describe a drawing that's very simple and symbolic. That drawing your cousin made of a house with a pointy roof, smiling stick figures, and a round yellow sun? Very schematic.
The word schematic can apply to ideas as well as drawings. In this case, schematic describes an overly simple interpretation of something complex, like a work of literature or a detailed plan for social change. Think of it like the drawing of a boxy house and stick figures, only applied to ideas — it's an outline of something that may not capture all the important details.
