Curtains For Plum

Dorothy has a L.L. Bean bed that is in the living room and that she will often lie upon.  Posy was fond of the bed when we first got it, but Plum ignored it--except for the time when he urinated on it, sigh.  However, last weekend Sean put curtains up in our living room, and one of the curtains hangs by Dorothy's L.L. Bean bed.  For some reason known only to little cat brains, the presence of the curtains hanging down by the bed have made it a desirable place to be.  Now every day Plum can be found on the bed by the curtains.

I do not understand why.