i(5,4,4,3,3,2,2,1,1; 1,1,2,2,3,3,4,4,5)
i(9,8,7,6,5,4,3,2,1; 1,2,3,4,5,6,7,8,9)
i(18,16,14,12,10,8,6,4,2; 1,2,3,4,5,6,7,8,9)
i(81,64,49,36,25,16,9,4,1; 1,4,9,16,25,36,49,64,81)