In this empirical study, the appropriation of a symbolic skill by a five-year old child is analysed. His evolving production and understanding are investigated through his sign-making and his explanations of these when speaking with a researcher. The child is studied in his home. A contrasting case of another child of the same age also making graphical signs in his home is used to clarify the nature of this evolving skill. The child goes from using deictic references, and in other ways indicating that he takes his signs to be self-evident to anyone, to becoming capable of formulating abstract principles. The productive use of physical separation in scaffolding the child to make an intellectual distinction is also noticed, and the issue of meta-communication, that is, communication about one's communication (representation, sign), appears to be the key not only to the development of the researcher's understanding of the child's skill but also to the child's development. (Contains 4 figures and 5 excerpts.)