Place the digits 1-9 once into each row, column, and 3x3 box. Digits must not repeat along the marked diagonal. The grey lines are palindromes and must contain the same sequence of digits in both directions along the line. The purple lines are Double Renban lines. Each such line contains two equal-sized sets of consecutive digits. The sets might overlap partially or completely, and the digits can be in any order along the line. For example, 123123, 172839, and 142332 are each valid ways to fill a six-cell Double Renban line.