The description on the back of the box explains the game quite well..'The unique characteristics of GRIDLOCK can be traced back to a puzzle-game played in Edwardian England around the turn of the century. It was particularly popular in the exclusive Gentleman's Clubs of London and was undoubtedly played for some kind of a stake. Two gentlemen would arrange 28 dominoes of a double-six set into an 8x7 grid of numbers. These grids, but not the actual locations of specific dominoes, were copied onto sheets of paper, which were exchanged between the contestants. The first to arrange his dominoes into a pattern that matched the numbers, but not necessarily the original domino arrangement, was the winner. By replacing the domino framework with one consisting of geometric shapes, GRIDLOCK expands this game concept into 50 distinct puzzles.'The game brings about 50 shapes and each puzzle uses about 12 different different ones.This game was published as part of 'the Hi-Q collection' - BoardGameGeek