Cubing the Square?
- XV and number dots
- Renban lines
The brief
Standard quattroquadri rules: all the digits from 1 to 9 must appear in each 3x3 box, and digits may not repeat in a row or column. Renban: a purple line must contain a non-repeating set of consecutive digits in any order. Anti-palindrome: digits equidistant from each end of a red line must sum to 10. XV pairs: digits separated by a V must sum to 5; digits separated by an X must sum to 10.