We present the iterative design of a virtual sandtray application for a tabletop display. The purpose of our prototype is to support sandtray therapy, a form of art therapy typically used for younger clients. A significant aspect of this therapy is the insight gained by the therapist as they observe the client interact with the figurines they use to create a scene in the sandtray. In this manner, the therapist can gain increased understanding of the client's psyche. We worked with three sandtray therapists throughout the evolution of our prototype. We describe the details of the three phases of this design process: initial face-to-face meetings, iterative design and development via distance collaboration, and a final face-to-face feedback session. This process revealed that our prototype was sufficient for therapists to gain insight about a person's psyche through their interactions with the virtual sandtray.