The instructional metaphor is an important bridge to understanding, particularly when students are undertaking tasks that are conceptually difficult and outside their previous experience. It is suggested that the limitations of the implicit metaphor of the procedural control languages are the main cause of the problems experienced with delivering the control topic within the Information and Communication Technology (ICT) curriculum. These continue to dominate classroom practice despite Papert warning more than 25 years ago of the conceptual restrictions that they place on children's thinking. It is also claimed that the procedural control languages do not provide an adequate representation of the underlying input-process-output model of control, and that this contributes to a systematic pattern of misunderstanding. Classroom trials of a graphic object-orientated language are related to a prior study made with the procedural control language "Control Logo". The relatively more sophisticated mental models developed by students working with "actor-lab" are discussed in terms of the different underlying metaphors and the problem representation provided.