The figure is here:
? ? __ __ __/__ __ __ __ __ __ \|__|__|__|__|__|__|__|__|__| |__|__|__|__|__|__|__|__|__|\ ? |__|__|__|__|__|__|__|__|__|\? \|__|__|__|__|__|__|__|__|__| ? |__|__|__|__|__|__|__|__|__|\ ? |__|__|__|__|__|__|__|__|__| ? \|__|__|__|__|__|__|__|__|__|\ |__|__|__|__|__|__|__|__|__| ? |__|__|__|__|__|__|__|__|__| / / / / / ? ? ? ? ?
To guard against any notational confusion, you may confirm that the number of cells in each diagonal, going around CW the top, is: (3, 1, 2, 4, 6, 1, 2, 3, 4, 8, 9, 2, 5, 8). Also, note that some cells are present in two diagonals and so contribute twice to the grand sum of 178.
The puzzle is from the site: "Cracking the Cryptic"