Here’s a Prime Place puzzle, another type from the upcoming GP round. Finally a type that forces me to deal with rendering irregular grids! I wonder if we’ll have a hex grid in one of the next rounds?
Rules Place a number between 1 and 4 into each cell, such that each number occurs exactly four times. The digit sum of each horizontal or vertical word must be prime. The digit sum of a diagonal word is prime precisely if that word is marked with a gray diagonal. Here, a word is a maximal straight line of connected cells; words may have length 1.
Or see the instruction booklet.