The goal of this paper is to explore dynamic geometry environments (DGE) as a type of computer programming language. Using projects created by secondary students in one particular DGE, we analyse the extent to which the various aspects of computational thinking--including both ways of doing things and particular concepts--were evident in their work, drawing specifically on frameworks for computational thinking that are designed for the purpose of mathematics education. We show how many of the practices associated with the use of propositional programming languages also feature in the more spatial and temporal register of the geometric "language" of DGEs.