A video can be viewed at the YouTube channel on Self-Modeling Networks: https://www.youtube.com/watch?v=MV0JtfWa6EA. Learning processes can be described by adaptive mental (or neural) network models. If metacognition is used to regulate learning, the adaptation of the mental network becomes itself adaptive as well: second-order adaptation. In this paper, a second-order adaptive mental network model is introduced for the metacognitive regulation of learning processes. The focus is on the role of multiple internal mental models, in particular, the case of visualisation to support the learning of numerical or symbolic skills. The second-order adaptive network model is illustrated by a case scenario for the role of visualisation to support learning multiplication at the primary school.