# Dimensions
    #
    #   (r,c)        <=== transpose ===>    (c,r)
    #
    # Data
    #
    # [ [ 1, 2 ],                         [ [ 1, 3, 5 ], 
    #   [ 3, 4 ],    <=== transpose ===>    [ 2, 4, 6 ] ]
    #   [ 5, 6 ] ] 
    #