Click an edge of the graph to make a tile. View options are found in “Show/Hide Elements”, and various dimer/tiling tools are in the “Tools” menu. Have fun!

Instructions

In the black rectangle: click to add a vertex, click the same vertex twice to delete it, and click one vertex and then another one (at least one in the black rectangle) to add an edge between the vertices. When you are satisfied, click "done" to generate the dual graph and examine tilings.

Click an edge to add or remove a tile.