Artistic computing learning environments have been of central importance in the exploration of how to support equity and inclusion in computing. Explorations within e-textiles, music, and interactive media, for example, have created diverse opportunities for learning how to program while creating culturally relevant artifacts. However, there is a gap in our understanding of the design processes of learners in these constructionist environments, including how the computational artifacts and their components impact the learning processes and the ways they build meaning and agency with computing. We advocate for research to attend more closely to the materiality of the computational materials to understand how they impact the social and cultural dimensions in which students are learning. In this paper, we present an analysis of 6 high school learners' experiences within a co-designed arts and computing curriculum. Our analyses highlight how the materiality of the components impacted the ways in which learners developed personal and epistemological connections to computing based on how it enabled them to connect to their interests, represent their ideas, engage with their community, and overcome or navigate around challenges to get to their final designs. We demonstrate how centralizing the materiality in the design of computational construction kits can inform how we support agency and engagement with computing.