Saw this was done by modifying the Woven Back Bench so I decided to give it a go. Added center 2x4 for support under the 1x4 slats. To make this bench modified the woven back bench shopping list to the following.
1-1x16x6 edge glue board.
Cut list was modified:
4-2x2 @ 16”
All other instructions were followed from the woven back bench.