Here is a fun little exercise about modularity. Enjoy!
Rules:
1. Normal sudoku rules apply.
2. Digits along the blue line have an equal sum N within each 3x3 box it passes through.
3. Blue lines are also modular lines. Any set of three sequential cells along a modular line contains one digit from (1,4,7), (2,5,8), and (3,6,9).
4. Cells separated by a white dot must contain consecutive digits. Cells separated by a black dot have a 1:2 ratio. Not all dots are given.
Do have a go!
Link(solution check): CTC
Solution code: Column 2