Litterbox Cafeteria

We finally took Duchess's urine to the vet for testing. This was easy to do, as recently she has been regularly laying out deposits of urine at locations around the litterbox. The good news is that she is not sick. The bad news is that she is rejecting our litterbox arrangements.
So, at the vet's recommendation, we have created a litterbox cafeteria. Or, as my mother suggests, a defecateria. We moved one of the original boxes into the bathroom, left the other original in the office, and added four new boxes. Four litterboxes (including 1 which is scented!) and four different types of litter. We've got your natural pine, your magical crystals, your wheat clumping litter, and your Arm and Hammer. So far, the Arm and Hammer has generated the least response. The cats don't even sniff it. The magical crystals, which look and feel just like rock salt, have given Duchess some amusement as she knocked them out of the pan. I can't blame her - I don't think it would be pleasant to walk on those.
We let Duchess thoroughly investigate the defecateria. After a thorough round of delicate sniffing, she elected to go into the dark bathroom and use the original box. The original box which she has rejected time and time again.