Here we used the "Gigi" patterned 13.75" squares on a shelf wall divider (vintage 1960's construction!) Simply stick on with adhesive tabs and secure with a few brad nails.
Originally they were designed with the IKEA EXPEDIT in mind, to cover the backside of the shelves if being used as a room divider or to add some interest to random cubes.
They also fit the IKEA EFFEKTIV cabinet doors.
WE will have examples of both for you shortly.