Strimko

Strimko is a logic number puzzle invented in 2008 by the Grabarchuk family. Like Sudoku and KenKen, Strimko asks the puzzle-solver to complete a Latin square under certain constraints.

A Strimko puzzle consists of an N×N grid of cells, partitioned into N regions of N cells each; these regions are called "streams." The solver's goal is to fill each cell with a number from 1 to N, such that no row contains the same number twice; no column contains the same number twice; and no stream contains the same number twice.