blindness

Last evening at dinner one of my brother's friends, and a potential business partner of my father's, remarked that I looked like my father (it is true). She then said that my brother must look like my mother. I said that he did, and added that my sister (who lives in Pennsylvania and was not at dinner) looks even more like my mother. "In fact," I added, "there have been times, seeing her, when I actually did a double-take, she looks so much like my mom. "I don't see it at all," my father said.