Taken from the December 2019 issue of Physics World.
In April this year, astronomers working on the Event Horizon Telescope captured the first direct images of a black hole and its “shadow” – the glowing ring of gas and dust trapped in a disc around them. Inspired by this revolutionary discovery, Physics World reader Michael Metcalf has created a variant of a traditional sudoku so that it begins with a central shadow surrounded by a bright region.
In this extra-large X-sudoku, each number from 1 to 16 must appear once in each row, column and 4 × 4 box, as well as in each of the two diagonals.
To help you test your mettle over the holidays, you can download a PDF of this puzzle. We will share the solution in the February edition of Physics World.
