The Big Book of Logic Puzzles - Fillomino 400 Hard (Volume 45)

Fillomino (also known as "Polyominous") is a type of logic puzzle. It is played on a rectangular grid of squares. Some cells of the grid start containing numbers, referred to as "givens". The goal is to divide the grid into blocks. The block must contain the number of cells indicated by the number in the cells of the block. The block cannot touch a similarly sized block, horizontally or vertically. Cells without numbers may form blocks necessary to complete the puzzle.