Not sure if this has been played here before or not. Choose the name that you prefer out of the two girl names, keep it and then add another name for the next poster to choose between. The same name could be chosen for several rounds or not at all. Would go like this; I will do a few rounds to demonstrate:
Anna or Gwendolyn Edited to add: Names can be similar style or very different.
Anna or Gwendolyn Edited to add: Names can be similar style or very different.