The purpose of this study is to gain a deep understanding of kindergarten children's drawings as a form of documentation of their work, of their ability to notice and depict substantial details, as well as their understanding of how objects in the world "work". In the study, we examined drawings created by kindergarten children for documenting artefacts they previously constructed. The drawing process demands the cognitive transition from the perception of the 3D object to its 2D drawing. Most theoretical and research work conducted over the years focused on children's free, intuitive and/or spontaneous drawing. As well, most studies focused on children drawings of given objects, even their copy of drawings of objects, or on free representation of ideas or feelings. In this study, we addressed two aspects that differ from the foci of previous work: (a) children drew an object they have constructed; and (b) the drawing has a functional purpose (i.e., documentation) as part of a design task. The study participants included 30 kindergarten children, aged 5-6. During freeform play, the children produced constructions using a building kit and documented these in drawings. A total of 39 constructions and corresponding drawings were analyzed. Data analysis was conducted to examine the characteristics of children's drawings, as well as the relationship between the features of the constructions and the corresponding drawings. The insights emerging from the study indicate that drawing can serve as a tool for documentation and reflection by kindergarten children and may support the development of technological thinking.