MacMahon Squares discoverer or inventor Percy Alexander MacMahon
MacMahon Squares is the name given to a recreational edge-matching puzzle first published by Percy MacMahon in 1921, where 24 uniquely 3-colored squares are organized next to each other by matching color to create a 4 by 6 grid. Such tessellation puzzles have multiple variants, which are determined by restrictions on how to arrange the 24 squares. This game has also been commercialized in numerous physical forms, by various companies.The game
MacMahon squares was first published in Percy Alexander MacMahon's 1921 treatise New Mathematical Pastimes. The original version consisted of one copy of each of the 24 different squares that can be made by coloring the edges of a square with one of three colors.  (Here "different" means up to rotations.)  The goal is to arrange the squares into a 4 by 6 grid so that when two squares share an edge, the common edge is the same color in both squares. 
In 1964, a supercomputer was used to produce 12,261 solutions to the basic version of the MacMahon Squares puzzle, with a runtime of about 40 hours.The MacMahon Squares game is an example of an edge-matching puzzle.  The family of such problems is NP-Complete.
There are a total of 24 distinct squares for 3 colors. For a given number of colors, the number of squares can be found by the expression 
  
    
      
        
          1
        
        
          /
        
        
          4
        
        n
        (
        n
        +
        1
        )
        (
        
          n
          
            2
          
        
        −
        n
        +
        2
        )
      
    
    {\displaystyle {1}/{4}n(n+1)(n^{2}-n+2)}
  .
discoverer inventor creator pioneer innovator