Each little section is cut out and then there is some silicon glue underneath one side to give it an undulating look - this might explain better
Whilst on this I thought I would show you the fold on my sample for JFF as the photograph did not portray it as it is. This is one in the making with the square missing at the moment.
So you just fold the front of your white card up as in the picture above, put a sheet of black card (A6) behind and stick down. Then place your square image on top. (See Thursday's post).