Contribution: This article presents a study that adds evidence to the field of computer education by focusing on the interaction between shapes of tables, group size, and gender, and their effects on on-task collaborative learning actions. By studying the collaborative learning environment in the context of computer education, the aim is to understand how different on-task actions are affected by the mentioned factors. Background: Previous research on collaborative learning space in the collaborative computer education context with the focus on the group formation, gender aspect, and analysis of on-task actions. Research Questions: Do different table shapes have different effects on open-ended computer education on-task actions for different groups sizes (two and three participants) and for different genders? Methodology: In order to study a collaborative problem-solving activity that is based on creating a prototype of a responsive toy, two main conditions were examined: table shape (round or rectangular) and how this interacts with group size (two or three participants) and gender. University students were engaged in design tasks conducted in small groups following the Jigsaw pattern. Findings: Results show that students engage more in interaction with physical artifacts when collaboration is conducted in dyads. In terms of gender, the analysis shows a tendency of female students to engage more when the activity is conducted in dyads. Furthermore, the combination of a dyad structure and a round table resulted in more discussion and nonverbal interaction.