Logic Masters Deutschland e.V.

The idea for this puzzle grew out of a wikipedia article about ‘syncopation’ in music. each line in the puzzle should be thought of as a bassline made up of riffs with different time signatures.

Rules:

• Standard sudoku rules apply.
• YIN-YANG - Shade some cells so that all shaded cells are orthogonally connected, and all unshaded cells are orthogonally connected. No 2x2 region can be completely shaded or unshaded.
• RIFFS - A 'riff' is sequence of digits such that (a) no digits repeat, (b) one of the digits is the length of the sequence, and (c) consecutive digits differ by at least 4. For example, "1", "82" and "59384" are all valid riffs.
• BASS LINES - A 'bass line' contains one or more copies of exactly two riffs, where copies of one riff lie over 'Yin' cells, and copies of the other over 'Yang' cells. Additionally, these two riffs cannot share any digits, and copies of riffs must read in the same direction along a bass line. For example, "82-82-82-395", "1-26-1-26", and "62-4817" are all valid bass lines.

Here's an example grid to demonstrate the ruleset: