There are many commercial information visualization tools that enable domain experts to create visualizations on their own. However, when the data and the domain is complex, the visualization design task is delegated to a visualization designer. In this case, the visualization designer works in close collaboration with domain experts and their knowledge of the domain evolves through prototyping visualizations. The visualization prototypes are designed programmatically or on paper. Therefore, we propose that visualization designers and domain experts should create visualizations together using a visualization tool. These visualization design activities can lead to discussion and criticism on existing representations and serve as important usability criteria for more useful designs. We designed PairedVis, a tool to support both experts, the visualization designer and the domain expert in creating visualizations together. We conducted a study to investigate whether PairedVis supports the two experts in sharing knowledge and discussing representations.