-- msk ([[1,2,3],[4,5,6]],0,3,9) 5 ~> error "unzulaessig"

msk ([[1,2,3],[4,5,6]],2,3,9 ) 5 == [[5,10,15],[20,25,30]]
msk ([[1,2,3],[4,5,6]],3,4,1 ) 5 == [[5,10,15,5],[20,25,30,5],[5,5,5,5]]
msk ([[1,2,3],[4,5,6]],2,2,9 ) 5 == [[5,10],[20,25]]

mm [[1,2,3],[4,5,6]] [[1,2],[3,4],[5,6]] (2,3,2,9) == [[22,28],[49,64]]
mm [[1,2,3],[4,5,6]] [[1,2],[3,4],[5,6]] (3,2,4,1) == [[7,10,3,3],[19,28,9,9],[4,6,2,2]]
mm [[1,2,3],[4,5,6]] [[1,2],[3,4],[5,6]] (1,3,1,9) == [[22]]

ms [[1,2,3],[4,5,6]] [[1,2,3],[4,5,6]] (2,3,9) == [[2,4,6],[8,10,12]]
ms [[1,2,3],[4,5,6]] [[1,2,3],[4,5,6]] (3,2,1) == [[2,4],[8,10],[2,2]]
ms [[1,2,3],[4,5,6]] [[1,2,3],[4,5,6]] (3,3,1) == [[2,4,6],[8,10,12],[2,2,2]]
ms [[1,2,3],[4,5,6]] [[6,5,4],[3,2,1]] (1,2,3) == [[7,7]]

-- mp [[1,2],[3,4]] (2,9) (-1) ~> error "unzulaessig"
mp [[1,2],[3,4]] (2,9) 0 == [[1,0],[0,1]]
mp [[1,2],[3,4]] (2,9) 1 == [[1,2],[3,4]]
mp [[1,2],[3,4]] (2,9) 2 == [[7,10],[15,22]]
mp [[1,2],[3,4]] (2,9) 3 == [[37,54],[81,118]]
mp [[2,2],[3,4]] (1,9) 3 == [[8]]