Circuitry

Title: Circuitry

Rating: 3/5

Back in October, I posted the first puzzle that had a "toral board." The additional rule is highlighted at the bottom, but it relies on the mathematical idea of a fundamental region.  I haven't consider any other fundamental regions as puzzle boards yet.

The official rules:

• The digits 1 through 9 appear in each row and each column exactly once.
• Digits in each shaded region must multiply to the indicated product.   
• Squares with multiple colors contain a number that’s used in the product for adjacent regions of each of those colors.  
• Remember: numbers can repeat within a shaded region if that doesn't violate the first rule. 
• The board is a “toral board,” that is, cells at the end of one row are considered adjacent to those at the beginning of the same row; cells at the end of one column are considered adjacent to those at the beginning of the same column, and all corner cells are considered adjacent.