Jem B, Y9
I decided to make a puzzle in the Japanese style (simple rules, no language requirements) and I came up with the below. I then wrote a program to solve these puzzles and also generate new ones.
The grid given has numbers and some boundaries between them. The goal is to add more boundaries to enclose blocks of numbers, such that each block contains the numbers from 1 to the size of the block: e.g. a size-1 block contains the number 1, a size-2 block contains the numbers 1 and 2, etc. Blocks may be of any size or shape.
Example puzzle The solution