I’m meaning to write up a report on the recently finished 24th WPC. No official results yet, but Ken Endo won the individual competition before Ulrich Voigt and Palmer Mebane, and we (Florian, Philipp, Ulrich and I) took gold with the team in front of Japan, Germany B (inofficial) and USA.

Instead, here’s a puzzle I made in preparation for round 9, which consisted of various puzzles built around the idea of marking several areas that had to be filled differently.

Rules Solve as a standard Tapa. Additionally, each gray 2-by-2 square must be shaded differently. E.g., no two gray squares can have only the top left corner shaded.

There are 15 gray squares, the different shades of gray are only there to make it possible to tell the squares apart.

Edit Here’s an alternate rendering, due to edderiofer.