The plane was always oriented with its underside toward the center of the screen, thus representing gravity. In the interviews, the interviewer controlled the computer program. Participation was voluntary, and in all, 19 children took part. However, in this analysis, excerpts from four children are included, and we use these as exemplars illustrating variations in children's reasoning. We selected four excerpts to illustrate three different ways of reasoning. This grouping is an analytical construction based on the manners in which the graphical representation was incorporated into the argumentation. On a general level, the development of reasoning and human knowing schematically visible in the four excerpts can be understood as related to the constant adjustment of human perception to evolving technologies. The overall aim of this study was to explore some of the relations between representational technologies, perception, cognition, and human action.