The concept of function has a central role both at school and in everyday situations. Several studies revealed that it is hard for students to think of functions and graphs in terms of covariation and this could contribute to their struggles in Calculus. The emergence of available technologies has fostered new teaching and learning approaches to overcome students' difficulties and some of them concerns the use of dynamic algebra and geometry software programs to experience the dependence relation and to explore functions as covariation. In this paper we describe a particular representation of functions with parallel axes and the analysis of a protocol in which three students work together on a problem that involves the exploration of a function represented in a dynamic interactive file. The analysis has been carried out to explore the potential of the proposed dynamic representation of functions that incorporates the semantic domain of space, time and movement.