Hi –When I was in woodworking school I made a pair of ladder back chairs. One of the special features of the chair came from resawing and milling the back slats so that the grain appeared to arch in center, like a sunrise. All of the wood I used was rough saw 8/4 cherry. I remember chalking out the blank at an angle within the billet, and then cutting the billet so as to create a rectangular slat blank that revealed upwardly arched grain when the back slat curve was carved. I have not been able to remember much else, including the name for this process, and thus have not had any success Googling.