The veneer grain is oriented horizontally, to match the hardwood strips.The joints between the side panels and the hardwood strips appear to be butt joints, but there must be internal dowels or biscuits to prevent panel movement. (It’s impossible for me to find out without cutting my cabinets open.)The veneer on the sides actually extends over the wood strips; you can see that the butt joint between the MDF and the hardwood is about 3⁄4” below (at the top) and above (at the bottom) where the veneer ends and the hardwood is visible. My theory is that the strips have a slight rebate cut into them for the veneer to cover and fill.