Spatial reasoning skills are necessary to perform activities at school, at work and in everyday life, in general. Different studies indicate the importance of its development at an early age, since it allows the reading of a three-dimensional world and its interpretation in two-dimensional representations. Our research focuses on the design of activities, using the Theory of Variation, to enhance spatial reasoning skills in seven to eight year-old students. In this document, we present characteristics of the design of an activity based on the use of pentominoes (two-dimensional puzzles). The results show that spatial reasoning skills develop when the following actions are favored: comparing, overlapping, rotating, moving, visualizing, and imagining movements, positions and locations of the pentomino pieces. [For the complete proceedings, see ED629884.]