Postscript to this post; June 13, 2018.
When I walked into the room where Concertinaed is displayed two evenings in a row I found the following:
Apparently a gust of wind from the open window combined with turning on a whole house ventilation fan blew the piece onto the floor. This is important to remember when displaying this work in spaces where air movement can lead to it blowing away. It did land gracefully.