MacMahon squares
The concept of colormatching tiles based on all the permutations of colors on their edges dates from 1926, when Percy MacMahon invented and introduced ThreeColor Squares and FourColor Triangles as mathematical pastimes.
MacMahon 3color squares

MacMahon divided squares and triangles into triangles to give each edge of a piece its own color, in all possible combinations. Each set contains 24 different tiles, and MacMahon discovered that they could form a single figure with all adjacent edges matching and just one color all around the outside border.
MacMahon 4color triangles

The most extensive research into these sets, over three decades, was done by the American engineer Wade Philpott (1918–85), of Lima, Ohio, who identified all the possible symmetrical shapes that MacMahon squares and triangles could solve with both matching edge colors and uniform border color, and who calculated all the numbers of solutions for the MacMahon squares' 4 × 6 rectangle.