Welcome
The Government Communications Headquarters (GCHQ) is a British intelligence and security organisation
We interrupted our Advent of Code to not only solve Robert Hannigan's much esteemed Christmas Card Puzzle, but to supplement their offering with an interactive version.
Each cell in the 25 x 25 square grid presented to your right must be shaded either black or white.
Some of the black squares have already been filled in for you. The numbers lining the rows to the left and columns above the grid indicate the length of all consecutive sets of black squares. The numbers are displayed in the order that each consecutive set appears in that line.
For a helpful example:
1 3 1 3 10 2 indicate consecutive sets of one, three, one, three, ten, and two black squares; each of which MUST be separated by one white square to complete a single row or column.