**UPDATE**Click here for a picture tutorial.
I started with 5x3" pieces of fabric and a 2x4" piece of heavy interfacing. I decided to make casings for the elastic along each of the long edges and cut one piece of elastic (from a cheap headband) to make it easier to loop over the door knobs.
The fabric and interfacing keep the door from latching so it can be opened and closed more quietly. I'm sending it to Elizabeth to put on Evelyn's door.