This study aims to contribute to the already existing findings of children's compositional strategies and products. Despite the abundance of research provided regarding the manner in which children approach composing, little has been found about how children deal, specifically, with the structure of the keyboard. Therefore, from a context in which children individually compose at the piano, the present study sets out to look at the thought processes and strategies that children elicit from the structure of the keyboard. Using examples collected from actual teaching practice, this article shows how children approach the keyboard in order to work out their own game rules, transpose dance patterns, derive musical phrases, form chiasmi and apply geometrical-mathematical principles, as well as how they break free from certain conventions and stereotypical models. The examples given show how musical thinking can be interwoven with non-musical ways of thinking, and how a visual-spatial approach of the keyboard can be influential.