Look at the video after he's taken the pieces out of the frame and reassembled them on the table—say, at 1m20s (http://youtu.be/_LY7mf49l5k?t=1m20s or screen shot here: http://imgur.com/GgxONLV). He's kept the two reassembled halves separate.
Look at the diagonal edges of the halves. They don't match up! I've put them together in Photoshop to make it clear: http://imgur.com/gsP6AxG When you put the two halves together, you don't get full cells. You get a crazy mishmash, because the height of one of the halves has been increased by 3/7ths of a cell-height. He replaced some pieces when he flipped the frame over.
Look at the diagonal edges of the halves. They don't match up! I've put them together in Photoshop to make it clear: http://imgur.com/gsP6AxG When you put the two halves together, you don't get full cells. You get a crazy mishmash, because the height of one of the halves has been increased by 3/7ths of a cell-height. He replaced some pieces when he flipped the frame over.