Seating Final Part 2

My 3 drivers were:
1.) Having strips of wood that go across the surface so that the ends remain ‘solid’ with no gaps and the number of strips can beadjusted.
2.) Amount of ribs that make up the internal structure
3.)Width and Lenght of the ribs.

The second and third prooved to be quite simple, while the first took a lot of tinkering with to get correct