I love this under stair indoor "dog house." Its out of the way and it even has a window. What more could a dog want? I do want this somewhere,so that while we are gone,they can look out of "their window" and watch for our return.
Simple built-in to create a mudroom and/or storage anywhere from an entry, to kids room or in a laundry room by adding shelves or a deeper bench for sitting. Put drawers under bench or have the seat lift up to store things.
STAIR IDEAS-- I love the idea of fairy lights along the banister. It gives a pretty effect and would be pretty for during Christmas time or a holiday season(this could also be used for all year round).
Line: The book shelf in the room shows the use of line because the book shelf shelves are built against the wall forming a miniature tree. Our eyes are drawn to look at the book shelf tree from bottom to top and outward to the tree/bookshelf branches.