I'm working on the countertop in my DIY motorhome. This is the working countertop hence the industrial look. Those ribs are separators. There will be more separators but making the small separators is proving challenging right now. I'll conquer them though. The reason for the separators - this countertop is dedicated to making electronics and programming microcontrollers. Thus one side (not shown) will hold trays of electronics. This side has a steel top - for soldering on and separators for tools etc.