Normal sudoku rules apply. Every digit on a line of colour C counts how many times that digit appears on all lines of colour C. For example, if there is a 3 on a green line, then there are exactly three 3s on all green lines combined. German whispers (decorated with squares): Adjacent digits along a green line differ by at least 5. Parity lines (decorated with circles): Adjacent digits along a red line have different parity (i.e., one of them is even and the other is odd). Region sum lines (no decorations): 3x3 box borders divide each blue line into segments of equal sum. The sum may be different for different lines.