This paper reports on the preliminary findings of an ongoing research on computer-supported collaborative design. A preliminary experiment was conducted to explore how groups of students collaborated in a colocated environment using a personal computer and around a conventional table. The observations of the experiment were on students' learning achievement, preference, and collaborative interactions using the two different types of interfaces. In this report, we discussed our findings on the collaborative interactions among the participants. The observations provide useful insights on how the application for an interactive tabletop should be designed to facilitate the co-ordination of co-located collaborative activity without disrupting the existing patterns of interactions.