The dog door. It’s an amazingly simple concept, simple to install, and simple to train the animals to use. It has been on my lengthy project list since moving to our yurt last May. Many other things have taken priority — until this week. My mother’s dog (Otis) is staying with us while they are off touring the South, with all its blooms and sunshine. We are now in the position of managing the capricious comings and goings of 3 dogs and 3 cats. After just two days with the addition of Otis, we have a newly installed doggie portal.