We investigated the nature of graphic formulas in 5-, 7-, and 9-year-old children when they were asked to draw a house and a television in a free condition, and then to draw from photographs of these objects. Assuming that the frequency of occurrence of a feature in children's drawings reflects its semantic weight, we studied the relations between occurrence and order of production of features to assess the extent to which a core-to-periphery progression principle (van Sommers, 1984) applies to the graphic formulas. The results showed that this principle was essentially present in the free drawing context. Under copying conditions, the order of production of the features was under the influence of perceptual and geometric factors, which elicited the production of subsystems of features at the depends of the application of the core-to-periphery progression principle. In the free condition, the core-to-periphery principle was mostly relevant in accounting for graphic formulas of the house in the young children (5 and 7 years), and of the television at ages 7 and 9. We suggest that the development of a graphic formula is partially related to the development of the object as a category in the child's conceptual system. (Contains 4 tables, 5 figures, and 2 footnotes.)